Cub Cadet T65 Series User Manual

Professional Shop Manual

T65 Series Vertical Shaft Engines

NOTE: These materials are for use by trained technicians who are experi enced in the service and repair of outdo or power

equipment of the kind described in this publication, and are not intende d for use by untrained or in experienced indi viduals. These materials are intended to provide supplemental information to assist the trained technician. Untrained or inexperienced individuals should seek the assistance of an experie nced and trained professio nal. Read, understand, and follow all instructions and use common sense when working on powe r e quip ment. T his includes the contents of the product’s Operators Manual, supplied with the equipment. No liability can be accepted for any inaccuracies or omission in this publication, although care has been taken to make it as complete and accura te as possible at the time of publ ication. However , due to the variety of outdoor power equipment and continuing product changes that occur over time, updates will be made to these instructions from time to time. Therefore, it may be necessary to obtain the latest materials before servicing or repairing a product. The company reserves the right to make changes at any time to this publication without prior notice and without incurring an obligation to make such changes to previously published versions. Instructions, photographs and illustrations used in this publication are for reference use only and may not depict actual model and component parts.

MTD Products Inc. - Product Training and Education Department

Table of Contents

Chapter 1: Introduction

Professional Service Manual Intent.................................................................... 1

Safety .................................................................................................................1

Fasteners ...........................................................................................................3

Assembly Instructions ........................................................................................3

Model and Serial Number ...................................................................................5

Maintenance .......................................................................................................5

Spark Plugs ........................................................................................................6

Air Filter.............................................................................................................. 7

Oil Type and Capacity ........................................................................................8

Changing the oil ...............................................................................................10

Fuel system ......................................................................................................11

Servicing the Fuel System ................................................................................11

Fuel Filter .........................................................................................................11

Valve lash .........................................................................................................12

Exhaust system ................................................................................................14

Cleaning the Engine .........................................................................................14

General Torque Specifications .........................................................................14

Chapter 2: Basic Troubleshooting

Definitions ........................................................................................................15

Introduction ......................................................................................................15

Steps to Troubleshooting .................................................................................15

Define the Problem ..........................................................................................15

Identify Factors that Could Cause the Problem ................................................17

Repairing the Problem ..................................................................................... 21

Prime Test ........................................................................................................22

Leak-down Test ................................................................................................22

Compression Test ............................................................................................24

PCV Testing .....................................................................................................25

Troubleshooting Flow Charts ...........................................................................26

Chapter 3: Air Intake System

Air Filter ............................................................................................................31

Air Filter Housing ..............................................................................................32

Carburetor Insulator .........................................................................................33

Fuel Line ..........................................................................................................37

Inspect the Fuel Lines ......................................................................................37

Chapter 4: The Fuel System and Governor

Inspecting the Fuel ...........................................................................................38

Test Fuel for Alcohol ........................................................................................38

The Fuel Filter ..................................................................................................39

Evaporative (EVAP) Emissions System........................................................... 39

Charcoal Canister Fuel Caps........................................................................... 39

Fuel Tank Vent .................................................................................................40

The Fuel Tank ..................................................................................................41

Autochoke ........................................................................................................42

Temperature Compensator ..............................................................................43

Primer ...............................................................................................................44

Carburetors ......................................................................................................45

Inspecting the Carburetor................................................................................. 45

Disassembly and Rebuilding the Carburetor ....................................................46

Governor ..........................................................................................................51

Governor Shaft .................................................................................................52

Governor Cup and the Governor Gear .............................................................54

Chapter 5: Lubrication

Oil Type and Quantity ...................................................................................... 55

Oil Dipstick .......................................................................................................56

Dipstick Tube Removal ....................................................................................57

Lubrication System ...........................................................................................58

PCV ..................................................................................................................59

Chapter 6: Starter and Charging Systems

Recoil Starter Removal ....................................................................................61

Starter Rope .....................................................................................................62

Starter Pulley and Recoil Spring ......................................................................64

Chapter 7: Ignition System 67

Troubleshooting the Ignition System ................................................................67

Troubleshooting the Stop Switch ..................................................................... 68

Troubleshooting the Module .............................................................................69

About the Spark Plug .......................................................................................72

Cleaning the Spark Plug .................................................................................. 72

Inspection of the Spark Plug ............................................................................72

Spark Plug Removal ........................................................................................72

Ignition Module................................................................................................. 73

Engine Brake and Stop Switch (if equipped) ....................................................74

Flywheel ...........................................................................................................75

Chapter 8: Exhaust

Muffler ..............................................................................................................77

Chapter 9: Cylinder Head

Cylinder Head .................................................................................................. 79

Valves ..............................................................................................................82

Chapter 10: Crankshaft, piston and Connecting Rod

Engine Disassembly..........................................................................................85

Crankshaft Inspection ......................................................................................88

Piston Inspection ..............................................................................................89

Connecting rod Inspection ...............................................................................91

Cylinder Inspection ...........................................................................................92

Bearings ...........................................................................................................93

Reassembly .....................................................................................................94

Engine Specifications Chart .............................................................................98

Engine Torque Values Chart ............................................................................99

Chapter 11: Failure Analysis

Abrasive Ingestion ..........................................................................................101

Insufficient lubrication .....................................................................................104

Engine Overspeed .........................................................................................106

Engine Overheat ............................................................................................107

Mechanical Breakage/ Wear ..........................................................................108

Detonation/pre-ignition................................................................................... 108

III

Introduction

Caution is used to point out potential danger to the technician, operator, bystanders, or surrounding property.

! CA UTION! CA UTION

Warning indicates a potentially hazardous situation that, if not avoided, could result in death or serious injury.

! WA RNI NG! WA RNI NG

! DANGER! DANGER

Danger indicates an imminently hazardous situation that, if not avoided, will result in death or serious injury. This signal word is to be limited to the most extreme situations

CHAPTER 1: INTRODUCTION

Professional Service Manual Intent

This manual is intended to provide service dealers with an introduction to proven diagnostic and repair proce-

dures for MTD T65 series vertical shaft engines. Disclaimer: The information contained in this manual is correct at the time of writin g. Both the prod u ct an d th e inf or -

mation about the product are subject to change without notice. About the text format:

NOTE: Is used to point out information that is relevant to the procedure, but does not fit as a step in the proce-

dure.

• Bullet points: indicate sub-steps or points.

1. Numbered steps 1a. Substeps

the actions required to complete a step.

Disclaimer: This manual is intended for use by trained, professional technicians.

• Using common sense in operation and safety is assumed.

• In no event shall MTD be liable for poor text interpretation or poor execution of the pro cedures described

in the text.

• If the person using this manual is uncomfortable with any procedures they encounter, they should seek

the help of a qualified technician or MTD Technical Support.

Safety

This Service Manual is meant to be used along with the Operator’s Manual. Read the Operator’s Manual and familiarize yourself with the safety and operational instructions for the equipment being worked on. Keep a copy of the Operator’s Manual for quick reference. Operator’s manuals may be viewed for free at the brand support website. It will be necessary to have the complete model and serial number for the equipment.

indicate specific things that should be done, and the orde r in whic h th ey sh ou ld be do ne.

will be lettered and nested within steps. Two or more substeps may be combined to describe

T65 Series Vertical Shaft Engines

• Be prepared in case of emergency: Keep a fire extinguisher nearby Keep a first aid kit nearby Keep emergency contact numbers handy

• Replace any missing or damaged safety labels on shop equipment.

• Replace any missing or damaged safety labels on equipment being serviced.

• Remember that some hazards have a cumulative effect. A single exposure may cause little or no harm, but continual or repeated exposure may cause very ser ious harm.

• Clean spills and fix obviously dangerous conditions as soon as they are noticed.

• Lift and support heavy objects sa fely and securely.

• Be aware of your surroundings and potential h azards that are inhe rent to all power equipment. All the labels in the world cannot protect a technician from an in stant of carelessness.

! CAUTION! CAUTION

• Grooming and attire: Do not wear loose fitting clothing that may become entangled in equipment. Long hair should be secured to prevent entanglement in equipment.

Jewelry is best removed.

• Protective gear: includes, but is not limited to

Clear eye protection ................................ while working around any machinery

Protective gloves ..................................... where necessary

Armored footwear.................................... when working around any machinery

Hearing protection ................................... in noisy environments

Chemically resistant gloves..................... when working with chemicals or solvents

Respirator................................................ when working with chemical or solvents

Appropriate tinted eye protection............. when cutting or welding

Flame resistant headgear, jacket, chaps. when cutting or welding

! WARNING! WARNING

• Exhaust fumes from running engines contain carbon monoxide (CO). Carbon

monoxide is a colorless odorless gas that is fatal if inhaled in sufficient quantity. Only run engines in well ventilated areas. If running engines indoors, use an exhaust evacuation system with adequate make-up air ventilated into the shop.

! DANGER! DANGER

Introduction

Fasteners

• Most of the fasteners used on the MTD engine are metric. Some are fractional inches. For this reason, wrench sizes are frequently identified in the text, and measurements are given in U.S. and metric scales.

• If a fastener has a locking feature that has worn, replace the fastener or apply a small amount of releasable thread locking compound such as Loctite® 242 (blue).

• Some fasteners, like cotter pins, are single-use items that are not to be reused. Other fasteners such as lock washers, retaining rings, and internal cotter pins (hairpin clips) may be reused if they do not show signs of wear or damage. This manual leaves that decision to the judgement of the technician.

Assembly instructions

• Torque specifications may be noted in the part of the text that covers assembly. They may be summa- rized in tables along with special instructions regarding locking or lubrication. Whichever method is more appropriate will be used. In many cases, both will be used so that the manual is handy as a quick-reference guide as well as a step-by-step procedure guide that does not require the user to hunt for information.

• Lubricant quantity and specification may be noted in the part of the text that covers maintenance, and again in the section that covers assembly. They may also be summarized in tables along with special instructions. Whichever method is more appropriate will be used. In many cases, the information will be found in several places in the manual so that the manual is handy as a quick-r eference g uide as we ll as a step-by-step procedure guide that does not require the user to hunt for information.

• The level of assembly instructions provided will be determined by the complexity of reassembly, and by the potential for damage or unsafe conditions to arise from mistakes made in assembly.

• Some instructions may refer to other parts of the manual for subsidiary pr ocedures. Th is avoids repeating the same procedure two or three times in the manual.

T65 Series Vertical Shaft Engines

MTD Vertical Engine Model Designators

Starter/Alternators

1=Recoil start 2=Electric start (12V) 3=E. start/alt. 18W 4=E. start/alt. 3A/5A 5= AutoChoke/ Recoil 6= AutoChoke/Electric Start 7= AutoChoke/Electric Start/Alt

1 P 6 1 M U A

P= Vertical (1 cyl.)

Q= Vertical (2 cyl.)

T= Vertical (1 cyl.)

X= Vertical (1 cyl.)

Bore Dia. (mm)

End Product

rettilpsgoLL)relffum on( rediRA

B Mower (long shaft M0) R Mower (long shaft/no shroud)

)duorhs on/tfahs gnol( rewoMMredderhS/reppihCC D Mower (long shaft M1) N Mower (short shaft M0) E Mower (short shaft M1) P Mower (long shaft M0) F Mower (short shaft/no shroud) Q Mower (short shaft M0)

G Garden Cart (Side Discharge) T Tiller

relliT dlroWW )relffu

m/w( rediRJ

Compliance

U United States (50 State) H Europe C California 0 (Zero) 49 State L 49 State - Special G U.S.(49) and Europe T Australia (S.A.) Y China W U.S.(50) and Europe

Major Revision

Change

MTD Engine Serial Numbers

Model number

1P65FH/0510271A0023

MonthYear

Producing Line# and Shift#: 1A=Line 1, 1

Shift

1B=Line 1, 2

Shift

2A=Line 2, 1

Shift

2B=Line 2, 2

Shift

3A=Line 3, 1

Shift

3B=Line 3, 2

Shift

4A=Line 4, 1

Shift

4B=Line 4, 2nd Shift

Date

Engine number

Introduction

Figure 1.1

Model /serial number

Dipstick

Model and serial number

The model and serial number can be found on a white sticker with a bar code. The sticker is usually located near the dipstick. See Figure 1.1.

NOTE: The serial number will always start with the model number.

Maintenance

The recommended maintenance intervals listed in this manual are a guideline. Local conditions may require

shorter service intervals.

Maintenance items Interval

Oil Change* 25 hrs Clean/replace spark arrestor** 25 hrs Replace the air filter 25 hrs Spark plugs 50 hrs Fuel filter 50 hrs Clean the engine 25 hours

* First oil change at 5 hours

**If equipped

T65 Series Vertical Shaft Engines

Figure 1.2

Spark plugs

The information in this manual applies to the MTD engine. Some basic principles may apply to engines produced by other manufacturers.

As the saying goes “an ounce of prevention is worth a pound of cure”. The same can be said about preventive maintenance on outdoor power equipment. By changing the spark plug and oil at recommended intervals many fai lures can be avoided.

NOTE: Please refer to Chapter 7: Ignition for the

complete service instructions on spark plugs.

1. The spark plug used in the T65 series engine is a F5RTC (part # 951-14437) gapped to 0.024” -

0.031” (0.60 - 0.80 mm). See Figure 1.2.

2. Wear rate will vary somewhat with severity of use. If the edges of the center electrode are rounded-off, or any other apparent wear / damage occurs, replace the spark plug before operating failure (no start) occurs.

3. Cleaning the spark plug: NOTE: MTD does not recommend cleaning spark plugs. Use of a wire brush may leave metal deposits on the

insulator that causes the spark plug to short out and fail to spark. Use of abrasive blast for cleaning may cause damage to ceramic insulator or leave blast media in the recesses of the spark plug. When the media comes loose during engine operation, severe and non-warrantable engine damage may result.

4. Inspection of the spark plug can provide indicati on s of th e op er a ting con d ition of th e en gine .

• Light tan colored deposits on insulator and electrode s is nor mal.

• Dry , black deposits on the insulator and electrodes indicate an over-rich fuel / air mixture (too much fuel or

not enough air)

• Wet, black deposits on the insulator and electrodes indicate the presence of oil in the combustion cham-

ber.

• Heat damaged (melted electrodes / cracked insulator / metal transfer deposits) may indicate detonation.

• A spark plug that is wet with fuel indicates that fuel is present in the combustion chamber, but it is not

being ignited.

Air filter

Figure 1.3

Foam filter

Paper-pleated element

The main function of the air filter is to trap air borne p articles before they reach the carburetor that can cause catastrophic internal engine damage.

MTD vertical shaft engines are equipped with one of two different air filters. The first is a round paper pleated filter. The second is a round foam filter. See Figure 1.3.

• Air filters used on the MTD engine are designed to prevent particles larger than 3-5 micron from passing through into the engine.

• The filter should be checked on a regular basis possibly several times in a season.

• Typically an air filter should be changed before every season.

• If a foam air filter is dirty, but not in bad of condition, it can be cleaned and reused. The paper pleated filters can be shaken or lightly tapped to free the debris from the filter.

Introduction

NOTE: Never use compressed air on a paper air filter . Compressed air will remove the tiny fibers that are used

to catch the dirt in the air. Without these fibers the filter is useless.

• Foam filters can be washed in warm soapy water.

NOTE: When drying a foam filter either squeeze it inside of a paper towel or let it air dry. DO NOT wring it.

Wringing the foam filter will cause damage to the foam.

NOTE: On foam filters, dry the filter throughly the n apply a couple of drops of motor oil. Gently work the oil

through the filter before installing it.

NOTE: Always check with factory specification prior to servicing/replacing any engine components.

T65 Series Vertical Shaft Engines

SAE 40

SAE 30

SAE 10W30/SAE 10W40

SAE 5W20

-4°F

14°F

32°F 50°F 68°F 86°F 104°F

-20°C

-10°C

0°C

10°C 20°C

30°C

40°C

Oil Chart

Oil type and capacity

The recommended oil for MTD engines is an SAE 10W-30 oil with an SM API rating or better . The oil capacity is

20 fl.oz (0.6 liters).

• Check the oil level daily, before starting the engine. Change the oil more frequently in severe operating conditions such as high ambient temperature, dusty conditions, or high load use in exceptionally thick grass.

• Synthetic oil is a suitable alternative, but it does not extend service interva ls.

NOTE: MTD recommends the use of petroleum oil during the break in period to ensure the piston rings cor-

rectly break in.

• Synthetic vs. Petroleum based oil: To simply look at synthetic oil and to compare it with Petroleum based oil there is very little difference. However, when you look at the two thro ugh a micro scope it is easy to see the difference. Synthetic is made up of smaller molecules. This allows the oil to get into areas that petroleum based oil cannot.

• No oil additives or viscosity modifiers are recommended. The performance of a good oil meeting the API specifications will not be improved by oil additives.

NOTE: Some oil additives may cause severe and non-warrantable engine damage, constituting a lubrication

failure.

NOTE: If the oil is noticeably thin, or smells of gasoline, a carburetor repair may be needed before the engine

can be run safely.

Introduction

Figure 1.4

1/4 turn

Threaded

1/4 turn

Threaded

Figure 1.5

Dip stick

Figure 1.6

Fully seat the dip stick before reading it

NOTE: There are two types of dip sticks that can be found

on the T series engine; a short threaded dip stick and a quarter turn extended dip stick See Figure

1.4.

To check the oil with a threaded dip stick:

1. Twist and remove the dip stick from the engine.

2. Clean the oil off of the tip of the dipstick.

3. Re-insert the dipstick without threading it in to get the oil level reading. See Figure 1.5.

4. The oil level is determined by the lowest point on the dipstick that is completely covered with oil.

To check the oil with a 1/4 turn dip stick:

1. Twist and remove the dip stick from the engine.

2. Clean the oil off of the tip of the dipstick.

3. Re-insert the dipstick and turn it until it is fully seated to get the oil level reading. See Figure 1.6.

4. The oil level is determined by the lowest point on the dipstick that is completely covered with oil.

T65 Series Vertical Shaft Engines

Figure 1.7

Siphon

Figure 1.8

Drain Plug

Figure 1.9

Changing the oil

NOTE: If the engine has been running, allow the

engine to cool before doing any maintenance work.

NOTE: The oil should be changed after the first 5

hours of operation and every 25 hours there after.

NOTE: There are three methods o f changing the oil.

Siphon the oil out through the dip stick tube

A. Insert the siphon hose into the dip stick tube. See

Figure 1.7.

B. Siphon the oil out of the engine by following the pro-

cedures provided by the siphon manufacturer.

Drain Plug in the bottom of the dipstick tube

A. Place an approved oil drain pan next to the base of

the dip stick.

B. Remove the drain plug using a 1/4” extension. See

Figure 1.8. C. Allow all of the oil to drain into the oil pan. D. Apply a small amount of releasable thread sealing

compound such as Loctite® 565 to the threads of

the drain plug. E. Install the drain plug, tightening it to a torque of 124

- 150 in lbs (14 - 17 Nm).

Tip the engine and application over

A. Drain the fuel out of the fuel tank. B. Place an approved oil drain pan on the ground. C. Lean the unit over on to the muffler side of the

engine. See Figure 1.9. D. Leave the application in this position until all of the

oil has drained out. E. Tip the unit back to its normal operating position.

Introduction

! CAUTION! CAUTION

Gasoline and its vapors are extremely flammable. Use common sense when working around the fuel system. Avoid sparks, open flames or heat sources that can ignite the fuel vapors.

Figure 1.10

Fuel filter

Fuel system

What you should know about fuel.

Most of the fuel presently available in North America is oxygenated to some extent. This is commonly done through the addition of ethanol. Most engines offered for sale on outdoor power equipment in the North American markets are designed to tolerate no more than 10% ethanol by volume

Ethanol is hygroscopic, meaning it absorbs water. If left exposed to air, it will draw water out of the air.

Ethanol is an oxygenator, which means that it will oxidize (corrode) metal that it comes into contact with. Exposure to air causes fuel to go bad quickly, leaving gum and varnish deposits.

Fuel used in MTD outdoor power equipment should be no more than 30 days old. Because it may already have been stored at the refinery or gas st ation for a week or mo re, fu el should be purchased in small quan tities and stored in safety approved gas cans with the caps closed.

For storage, all fuel should be run out of the tank and engine. Anti-oxidation additives will help keep the fuel fresher.

Servicing the fuel system

Inspect the fuel system every time the engine is operated. If dirty fuel is found in the fuel tank or fuel that does not smell “right”, drain the fuel tank and replace the fuel filter. Dispose of bad fuel in a safe and legal manner.

Refer to the units service manual for the procedures to drain the fuel tank.

Fuel filter

1. The fuel filter is installed in the fuel tank where the fuel line connects. See Figure 1.10.

T65 Series Vertical Shaft Engines

Figure 1.11

Spark plug hole

High tension lead

Muffler

(plug removed)

Figure 1.12

Valves closed

(push rods slack)

Probe to confirm piston

is at top of travel

Valve lash

Valve lash is the clearance between the top of the valve stem and the rocker arm. The valve lash should be checked after the first 25 hours of use and ever y 100 hour s a f ter th at. Valve lash can be checked and adjusted using the following steps:.

1. If the engine has been run, allow it to cool thor-

oughly. Position the mower for easy access to the cylinder head.

2. Disconnect the high-tension lead from the spark

plug and ground it well away from the spark plug hole.

3. Remove the spark plug using a 13/16” or 21mm

wrench. A flexible coupling or “wobbly” extension may help. See Figure 1.11.

4. Remove the four bolts that secure the valve cover

using a 10mm wrench, and remove the valve cover from the engine.

NOTE: If care is used not to damage the valve

cover gasket, it can be re-used.

5. Confirm that the piston is at T

on the compression stroke. See Figure 1.12. NOTE: An old plastic dip stick makes a nice probe

to check for TDC.

• The compression stroke can be distinguished from the overlap stroke by the presence of air pressure at the spark plug hole and the fact that neither of the valves should move significantly on the compression stroke.

• There is an automatic compression release mechanism that “bump s” the exhaust valve a s the piston rises on the compression stroke. At TDC, th e exhaust valve should be fully closed.

op-Dead-Center (TDC)

Introduction

Figure 1.13

0.005” feeler gauge

Setting intake valve lash

Figure 1.14

Setting exhaust valve lash

gauge

0.007” feeler

6. Check valve lash between each valve stem and rocker arm using a feeler gauge.

7. Intake valve lash (top valve) should be 0.004” -

0.006” (0.10 - 0.15 mm). See Figure 1.13.

8. Exhaust valve lash (bottom valve) should be 0.006” -

0.008” (0.15 - 0.20 mm). See Figure 1.14.

11. Double-check the clearance after tightening the jam nut, to confirm that it did not shift. Re-adjust if necessary.

12. Rotate the engine through several compression cycles:

13. Clean-up any oil around the valve cover opening, clean the valve cover, replace the valve cover gasket if nec-

14. Install the valve cover, tightening the valve cover screws to a torque of 62 - 80 in-lbs (7 - 9 Nm).

9. Use a 10mm wrench to loosen the jam nut, and a 14mm wrench to adjust the rocker arm fulcrum nut. See Figure 1.14.

• Tighten the rocker arm fulcrum nut to close-up the

clearance between the end of the valve stem and the contact point on the rocker arm.

• Loosen the rocker arm fulcrum nut to open-up the

clearance between the end of the valve stem and the contact point on the rocker arm.

10. Hold the fulcrum nut with a 14mm wrench, tighten the jam nut to a torque of 80 - 106 in-lb. (9 - 12 Nm) using a 10mm wrench.

• Observe the movement of the valve gear.

• Return the piston to TDC compression stroke and re-check the valve lash.

essary.

IMPORTANT: Over tightening the valve cover will cause it to leak.

15. Install the spark plug.

16. Te st ru n th e en gin e befo r e returning it to service.

T65 Series Vertical Shaft Engines

41M 21M 01Mezis 8M 6M 5M

4Mezis

347261sbl-tf398322

1sbl-ni8.4 edarG

856.637.12mN5.013.45.22.1mN

5553

02sbl-tf021058251sbl-ni8.5

675.741.72mN6.317.52

791653sbl-tf612881562sbl-ni8.8

2317.285.74mN

4.4

98.5

9.2

6316894sbl-tf0034212763sbl-ni

9.0

4816.6114.6

mN9.3

1.8

1.4

261

6sbl-

tf063641

44sbl-ni

9.2

7.93

4.18

7.0

5.61

7.9

075452sbl-tf051065381sbl-ni

59169.33mN7

8.6

lacitircno

ni srenetsa

munimulA

Exhaust system

The exhaust system is a frequently overlooked component of an engine. It is important to make sure the muf f ler is in good condition and free of blockage.

NOTE: A blocked muffler will result in poor performance. If a muffler is completely blocked, the engine may not start.

Cleaning the engine

1. To maintain a proper operating temperature and to keep the equipment looking good, all debris should be removed from around the engine.

2. It is recommended to use compressed air to blow all of the debris off of the engine. NOTE: A pressure washer may be used to clean outdoor power equipment but only after the unit has been

allowed to properly cool.

General torque specifications

Definitions

! CA UTION! CA UTION

The first two rules in troubleshooting is to cause no further harm to the engine and prevent injuries. Always make sure to check the oil for level and condition before starting an engin e. Also check attachments for damage and make sure they are firmly mounted.

Basic Troubleshooting

CHAPTER 2: BASIC TROUBLESHOOTING

Troubleshooting Diagnosis

shooting.

Introduction

Diagnosing an engine is an art form that is built upon several factors. First and most importantly is a good understanding of how the engine works. The second is skills that have been honed by experience. Finally the use of visual observations and a structured, systematic approach to troubleshooting a problem.

The first part of this chapter will outline the steps of troubleshooting an engine so a technician can form a proper diagnosis. The second half of this chapter will describe specific procedures and tests to perform while troubleshooting.

Steps to troubleshooting

NOTE: The steps and the order of the steps that follow are a suggested approach to troubleshooting the MTD

Define the problem

The first step in troubleshooting is to define the problem:

- The act of gathering information by preforming tests and direct observations.

- Developing and testing theories of what the problem is, based on the information gathered in trouble-

engine. The technician does not necessarily have to follow them as described in this chapter.

• Crankshaft will not turn. A. Starter not working. B. Engine in a bind (external - attachment jammed). C. Engine in a bind (internal - engine seized).

• Crankshaft turns, no start.

• Starts, runs poorly. A. Starts, then dies. B. Runs with low power output. C. Makes unusual smoke when running.

I. Black smoke, usually heavy. II. White smoke, usually heavy. III. Blue smoke. usually light.

D. Makes unusual sounds when running.

I. Knock II. Click III. Chirp

T65 Series Vertical Shaft Engines

IV. Unusual exhaust tone.

There are tools that the technician can use in order to define the problem, such as:

1. Interview the customer. 1a. Get a good description of their complaint. 1b. If it is an intermittent problem, verify what conditions aggravate the problem as best as possible. 1c. Get an accurate service history of the equipment. 1d. Find out how the customer uses and stores the equipment.

2. Direct observation: 2a. Do not automatically accept that the customer is correct with their description of the problem. Try to

duplicate the problem.

2b. Check the general condition of the equipment (visually).

I. Cleanliness of the equipment will indicate the level of care the equipment has received. II. Make sure the engine and attachments are securely fastened. III. The tune-up factors.

NOTE: Most hard starting and poor running conditions can be solved by performing a tune-up.

a. Check the conditio n and amount of oil in the crankcase. b. Check the level and condition of the fuel. c. Check the ignition and “read” the spark plug. d. Look for obvious signs of physical damage, exhaust system blockage or cooling system block-

age.

Identify factors that could cause the problem

This is the second step in the troubleshooting process.

1. Crankshaft will not turn.

Basic Troubleshooting

A. Starter not working

I. A dead battery. II. A bad ground. III. A failure in the electrical circuit. IV. A failure of the starter itself.

B. Engine in a bind (external - atta ch men t jamme d)

the engine either failed or has something jammed in it, locking up the system.

C. Engine in a bind (internal - engine seized)

likely suspects are: I. Complete hydraulic lock (easy fix). II. Bent crankshaft. III. Interna l binding, crankshaft, connecting rod or piston.

2. Crankshaft turns, no start. 2a. Most gasoline engine diagnosis involves isolating problems in the four critical factors an engine needs to

run properly:

I. Ignition II. Compression

needs sufficient sealing to generate the vacuum needed to draw in and atomize the next intake charge.

- sufficient spark to start combustion in the cylinder, occurring at the right time.

. This can be an electrical failure or a mechanical failure. The likely suspects are:

. This usually indicates that the unit being powered by

. This is usually either a quick fix or a catastrophic failure. The

- enough pressure in the cylinder to convert combustion into kinetic motion. It also

III. Fuel

IV. Flow

2a. Isolate the ignition system and compression from the fuel system by preforming a prime test.

I. Burns prime and dies. This would indicate a fuel system issue. II. Does not burn prime. Not a fuel system issue. Check for an ignition, compression or flow problem.

2c. Compression or ignition problem.

I. Check the engine stop and safety switch. II. Test the ignition system using a proper tester. III. Replace the spark plug with a new one or a known good one. IV. Check compression or leak down. V. Check valve lash. VI. Check valve timing/actuation. VII. Check exhaust.

3. Starts, runs poorly. 3a. Starts, then dies.

- correct type and grade of fresh gasoline; in sufficient q uantity, atomized (tiny droplets) and in

correct fuel/air proportions.

- if all of the above conditions are met but the flow of air is constricted on the inlet or exhaust side, it will cause the engine to run poorly or not at all. This also includes ensuring the valves are timed to open at the proper time.

T65 Series Vertical Shaft Engines

I. Run the engine with a spark tester in-line between the sp ark plug wire and the sp ark plug or use an

oscilloscope and see if the spark goes away at the same time the engine dies.

II. Check choke operation.

a. Black smoke? b. Wet plug?

III. Prime test immediately after engine dies. If it restarts, this may indicate a problem with fuel flow to

the carburetor. Check the gas cap, fuel line, fuel filter, and the float in the carburetor.

3b. Runs with low power output.

I. Look for unusual exhaust color (smoke). II. Unusually hot muffler (may glow red).

a. Retarded ignition. b. Exhaust valve opening ea rly (lash too tight).

III. Mechanical bind.

a. A slightly bent crankshaf t. In some cases the drag may increase and decrease as the crankshaf t

rotates. This produces a pulsing feeling that is different than a jerk back. b. Parasitic external load. A bind in the equipment the engine is powering. c. Internal drag from a scored piston or similar damage.

IV. Low governor setting or stuck governor.

a. Check RPMs using a tachometer. b. RPMs should not droop under moderate to heavy loads.

V. Low comp re ss ion .

a. Check valve lash. b. Check compression. c. Check leak down to identify the source of the compression loss.

VI. Flow blockage.

a. Exhaust blockage, usually accompanied by an unusual exhaust sound.

• Just as a throttle on the carburetor controls the engine RPMs by limiting the amount of air an engine can breathe in, an exhaust blockage will limit engine performance by constricting the other end of the system.

• The muffler itself my be blocke d.

• The exhaust valve may not be opening fully, possibly because of extremely loose valve lash settings.

• The exhaust valve seat may have come loose in the cylinder head. This may cause a loss of compression, a flow blockage or it may randomly alternate between the two.

NOTE: The cause of an exhaust valve coming loose is usually over heating.

b. Intake blockage.

• An intake blockage up-stream of the carburetor will cause a rich fuel/air mixture and constrict the amount of air that the engine can dr aw in, limitin g pe rf or ma n ce .

• The intake valve not fully opening. A possible cause of this is loose valve lash.

V. Makes unusual smoke when running.

Basic Troubleshooting

a. Black smoke

• Not enough air: air flow blockage or a partially closed choke.

• Too much fuel: carburetor float or float valve stuck or metering / emulsion issues with the carburetor.

b. White smoke

• Oil in muffler, usually the result of improper tipping. The engine will “fog” for a minute or so, then clear-up on its own.

• Massive oil dilution with gasoline. It may be caused by improper tipping. It can also be caused by leaky carburetor float valve, if there is a down-hill path from the carburetor to the intake port. Check oil for gasoline smell, repair carburetor.

c. Blue smoke,

PCV system.

• May be blocked or unplugged.

• May be over-come by massive over-filling or oil dilution with gasoline.

• Will cause oil to exit the engine via any low-resistance paths.

Piston rings.

• Confirm with leak-down test.

• Smoke will be more pronounced under load.

, usually heavy, usually indicates a rich air fuel mixture.

, usually heavy.

usually light.

• Repair may not make economic sense.

Valve gu ide s (a nd intake valve ste m sea l).

• Smoke will be more pronounced on over-run.

VI. Makes unusual noise when running.

a. Knock

• Check for loose mounting of engine or driven implement.

• Rotate crankshaft back-and-forth to check for loose connecting rod.

b. Click

• Clicks and pops on engine shut-down: Compression release coming into play as the engine RPMs cross the activation threshold. This will have no ill effects on engine performance.

• Half-engine speed clatter: loose valve lash.

• Half-engine speed clatter, slightly heavier: wrist-pin.

• Rhythmic heavy-light engine speed click: piston slap.

c. Spark-knock

• Advanced ignition timing.

• Low octane fuel.

• Over-heating engine (check for blocked cooling air flow).

• Carbon build-up in cylinder: glowing carbon chunks pre-igniting air fuel mix.

d. Chirp

• Compression, blowing-by the fire-ring of a damaged head gasket will sometimes produce a

T65 Series Vertical Shaft Engines

chirping noise.

• Confirm with a compression test and leak-down test.

e. Unusual exhaust tone.

Splashy

• Splashy idle usually indicates a slight rich condition.

• May indicate an exhaust blockage, usually slightly muffled. Backfire

• On over-run: unburned fuel igniting pa st ex haust valve . Mixture no t bur ning com pletely in combustion chamber. It may be too rich or it may be spark-plug or ignition problem.

• Occasional, under load: engine momentarily runs lean, usually will cycle with float bowl level or governor pull-in, sometimes sounds like a slight stumble. Ethanol content exceeding 10% will make the engine run artificially lean.

Skip

• Usually ignition related.

• Run the engine with a spark tester in-line between the spark plug wire and the spark plug or use an oscilloscope and see if the spark goes away at the same time the engine dies.

4. Engine over-speed A. Continual over-speed.

• Binding or damaged external governor linkage or carburetor thro ttle.

• Mis-adjusted governor arm.

• Internal governor failure.

B. Momentary over-speed.

• Intermittent bind (very unusual).

• Interference: This is fairly common when debris can fall on the governo r linkage d uring n ormal operations.

5. Engine RPMs surge (hunting). A. Over-governed condition- Return spring replaced with wrong part or hooked into wrong hole.

NOTE: This is an extremely rare condition, usually created by tampering.

B. Lean Air-fuel mixture condition- When AFR (Air Fuel Ratio) is significantly below stoichiometric ratio

(14.7:1) engine RPMs sink until they reach a po int tha t can be su pp or te d by the availa b l e fuel . Th is causes a momentary surge in power until the available fuel is consumed, then the RPMs fall again, repeating the cycle.

• Too much air: look for an air leak in the intake tract.

• Not enough fuel: look for fuel supply or carburetor problems.

Basic Troubleshooting

Repairing the problem

The third step in the troubleshooting process is to repair the problem. This step consists of:

A. Form a diagnosis by using all of the information gathere d from the tro ub leshoo ting th at was p erforme d. B. Physically perform the repair.

The fourth, and hopefully final, step in the troubleshooting process is the follow through. This step consists of:

A. Thoroughly test the repaired equipment: confirming that the initial diagnosis was correct. If it was

wrong, start the troubleshooting process over again.

NOTE: Sometimes the engine will have multiple problems at the same time. By performing one repair, other

issues may show up that are unrelated to the first repair.

B. Delivery to customer: We are not just repairing equipment, we are repairing customers.

• Inoculate against recurring problem with educa tion, e.g.: if the problem was caused by stale fuel, make sure the customer is aware that fuel go es bad ove r tim e.

• Make sure the customer understands the repair, preventing “superstitious” come-backs.

T65 Series Vertical Shaft Engines

! CA UTION! CAUTION

If the engine is not centered at top dead center, the engine will rotate when compressed air is introduce to the combustion chamber.

Figure 2.1

Leak-down

tester adapter

Prime test

To perform a prime test:

1. Prime the engine through the carburetor throat using a squirt bottle, filled with clean fresh gasoline.

2. Make sure the throttle is in the run position.

3. Attempt to start the engine.

4. If the engine starts and runs long enough to burn the prime, the problem is effectively isolated to the fuel system. Proceed to Chapter 4: The Fuel System and Governor.

5. If the engine did not start, check ignition system as described in Chapter 7: Ignition System.

6. If the ignition system is working, check the compression or perform a leak down test.

Leak-down test

A leak-down test is the preferred method to test the engine’s ability to compress the charge. It will also show where pressure is leaking from.

To perform a leak-down test:

NOTE: A leak down test pressurizes the combustion chamber with an external air source and will allow the

technician to listen for air “leaking“ at the valves, piston rings and the head gasket.

NOTE: These are general instructions. Read and follow the instruc tions that came with the tester before

attempting to perform this test.

• If possible, run the engine for 3-5 minutes to warm up the engine.

• Remove the spark plug and air filter.

• Find top dead center of the compression stroke.

1. Find top dead center by following the steps described in the valve lash section of Chapter 1: Introduction.

2. Thread the leak down tester adapter into the spark plug hole. See Figure 2.1.

Basic Troubleshooting

Figure 2.2

Regulator

knob

Valve

3. Connect tester to compressed air.

4. Adjust the regulator knob until the needle on the gauge is in the yellow or set area of the gauge. See Figure 2.2.

5. Connect the tes te r to th e ad ap te r.

NOTE: Open the valve, if equipped. NOTE: If the engine rotates it was not at top dead center.

6. Check the reading on the gauge.

7. Compare the results to the following chart.

Leak-down Testing Results

Symptom Possible cause

Air escaping from the breather

Air escaping from

Worn cylinder or piston rings. Possible blown head gasket

Leaking exhaust valve

the exhaust Air escaping from

Leaking intake valve

the carburetor Gauge reading

low Gauge reading

moderate Gauge reading

high

Cylinder and piston rings are in good condition

There is some wear in the engine, but it is still usable

excessive wear of cylinder and/ or piston rings. Engine should be short blocked or it could be a blown head gasket.

T65 Series Vertical Shaft Engines

Figure 2.3

Compression gauge

Compression test

To perform a compression test:

NOTE: Compression should be in the range of 55 - 85 PSI (3.8 - 5.9 Bar).

• Disconnect the high-tension lead from the spark plug and ground it well away from the spark plug hole.

• Remove the spark plug using a 13/16” or 21mm wrench. A flexible coupling or “wobbly” extension may help.

• Pull the starter rope several times to purge any fuel or oil from the combustion chamber.

NOTE: Air compresses readily, liquid does not. Liquid in the combustion chamber will result in an artificially

high compression reading.

1. Install a compression gauge in the spark plug hole.

2. Confirm that the gauge is “zeroed”, then pull the starter rope repeatedly, until the needle on the gauge stops rising. See Figure 2.3.

3. Interpreting compression readings.

Readings in

psi

<20 (1.4 Bar)

20 - 55 (1.4-3.8 Bar)

55 - 85 (3.8-5.9 Bar)

>85 (>5.9 Bar)

Compression Readings

Possible causes

Most likely a stuck valve or too tight of a valve lash, provided the starter rope pulls with normal effort.

Valve seat damage or piston ring and/or cylinder wear.

Normal readings

Excessive valve lash, a partial hydraulic lock, a bad cam or a bad automatic compression relief.

PCV testing

Figure 2.4

Breather

Breather hose

Figure 2.5

Basic Troubleshooting

The PCV (Positive Crankcase Ventilation) valve is located in the engine block and allows the crankcase pressure to escape.

Leakage and blockage are the two failure modes for a PCV system. Either mode will cause crankcase pressure to build-up, though the effects of a blocked PCV are gene rally more dramatic. Increased case pressure will result in oil entering the combustion chamber.

NOTE: The PCV chamber is vented to the air filter th rough

a molded rubber hose. The rubber hose directs crankcase fumes to a covered duct within the air filter housing. See Figure 2.4.

To measure the crankcase pressure:

1. Remove the dipstick.

2. Attach a manometer to the dipstick tube.

3. Start the engine.

4. Read the measurement on the manometer. See Figure 2.5.

NOTE: Less than (between zero and -1”) (-2.54cm) of

water is a typical reading.

NOTE: Experimentation by MTD’s Training and Education

Department has revealed the following characteristics of MTD engines:

• A leaky PCV system will not build-up substantial

case pressure.

• A leaky PCV system will allow the engine to ingest

contaminants through the system, accelerating engine wear.

• A blocked PCV system will allow crankcase pres-

sure to build very rapidly. Noticeable oil fumes will be evident in the exhaust within several minutes of normal operation.

T65 Series Vertical Shaft Engines

Ignition Troubleshooting

Engine will

not start

Engine runs

erratically or shuts

off, restarts

Check for spark

Spark No Spark

Check for the correct spark

plug

Check flywheel and key for

damage or sheared key

Set proper air gap on

ignition module

Test ignition module

for intermittent or

weak spark

Check electric starter and

battery if applicable

Replace spark plug

Isolate engine from

equipment and repeat

test

Spark No Spark

Equipment problem,

check switches, wiring

and equipment controls

Engine problem, check

for shorts or grounds in

wiring

Disconnect ignition

ground-out wire at

the ignition module &

repeat test

Check for proper air gap

on ignition module

and repeat test

Check flywheel magnets

for strength

Test ignition module

Troubleshooting flow charts

Engine Operation Problems

Excessive engine loading

OVERHEATS

Low oil level or wrong viscosity oil

Cooling air flow obstructed or

clogged cooling fins

Carburetor improperly adjusted or

improper RPM setting*

Ignition timing or

incorrect spark plug

Carbon in the combustion

chamber

ENGINE KNOCKS

Check for excessive carbon in

combustion chamber

Loose flywheel examine key, key way

and proper flywheel nut torque

Ignition timing or

incorrect spark plug

Loose or worn connecting rod

Worn cylinder

Associated equipment loose or

improperly adjusted

Basic Troubleshooting

T65 Series Vertical Shaft Engines

SURGES OR RUNS UNEVENLY

Fuel cap vent obstructed

Dirty carburetor or air filter

Carburetor improperly adjusted

Governor sticking, binding or

improper RPM setting

Carburetor linkage, shafts or shutters sticking or binding

Intermittent spark, check ignition

or incorrect spark plug

Oil level above full

Wrong viscosity oil

Engine cooling fins dirty causing

overheating

Breather damaged, dirty or

improperly installed

Excessive engine speed

Damaged gaskets, seals or "O" rings

EXCESSIVE OIL CONSUMPTION

Valve guides worn excessively

Worn or glazed cylinder

Piston rings worn

Lean carb setting causing

overheating (adjustable carb)

Engine Operation Problems

ENGINE MISFIRES

Improper Valve Lash

Weak valve spring

Excessive carbon build up

Carburetor improperly adjusted

Ignition timing or

incorrect spark plug

Valves sticking or not

seating properly

Wrong or fouled spark plug

Bent crankshaft

ENGINE VIBRATES

EXCESSIVELY

Attached equipment out

of balance

Loose mounting bolts

If applicable counter balance not

properly aligned

Engine Operation Problems

Basic Troubleshooting

T65 Series Vertical Shaft Engines

BREATHER PASSING OIL

Oil level too high

Breather damaged, dirty or

improperly installed

Damaged gaskets, seals

or "O" rings

Excessive RPM or improper

governor setting

Angle of operation too severe

Piston rings not properly seated or ring end gaps are aligned

LACKS POWER

Air intake obstructed

Lack or lubrication or improper

lubrication

Carburetor improperly adjusted

Exhaust Obstructed

Improper valve lash

Loss of compression (worn rings,

blown head gasket)

Engine Operation Problems

Air filter

Figure 3.1

Figure 3.2

Air filter

AIR INTAKE SYSTEM

CHAPTER 3: AIR INTAKE SYSTEM

To access the air filter: NOTE: The T65 engine comes equipped with either a

pleated paper filter or a foam filter. The procedure to access the filter is the same for both types.

1. Rotate air filter cover counter-clockwise. See Figure

3.1.

2. Pull cover off of the engine.

3. Remove the air filter. See Figure 3.2.

4. Install by following the above steps in reverse order.

T65 Series Vertical Shaft Engines

Figure 3.3

Nuts

Figure 3.4

Primer line

Breather hose

Figure 3.5

Squeeze the barbs together,

then push

Air Filter Housing

To remove the air filter housing:

1. Remove the air filter by following the steps described in the previous section.

2. Remove the two nuts that hold the air filter body to the carburetor mounting studs. See Figure 3.3.

3. Disconnect the breather hose. See Figure 3.4.

4. Disconnect the primer line, if equipped. See Figure

5. Lift away the filter housing.

6. The primer can be removed from the air filter hous-

3.4.

ing by squeezing together the two sets of barbs while pushing the primer out of the housing. See Figure 3.5.

Carburetor Insulator

To avoid personal injury or property damage, use extreme care in handling gasoline. Gasoline is extremely flammable and the vapors are explosive. Serious personal injury can occur when gasoline is spilled on yourself and/or your clothes which can ignite. Wash your skin

and change clothes immediately

! WAR N IN G! WAR N IN G

Figure 3.6

Figure 3.7

Tin gasket

Autochoke Linkage Bracket

AIR INTAKE SYSTEM

To remove/replace the carburetor insulator:

1. Remove the air filter housing by following the previously described steps.

2. Remove the carburetor. 2a. Clamp off the fuel line. 2b. Disconnect the fuel line from the carburetor. 2c. Drain the fuel tank in to an approved container . 2d. Remove and discard the fuel line. See Figure

3.6.

NOTE: Disconnecting the fuel line causes tiny tears in the

inner lining of the fuel line. These tears will collapse the inner lining, cutting off fuel flow.

NOTE: If the engine is not equipped with an autochoke,

skip ahead to step 2l.

2e. Remove the recoil starter by following the pro-

cedures described in Chapter 6: Starters 2f. Lift the blower housing off of the engine. 2g. Remove the tin gasket. See Figure 3.7. 2h. Remove the Autochoke Linkage Bracket. 2i. Remove the carburetor gasket.

T65 Series Vertical Shaft Engines

Figure 3.8

Air vane

Choke rod

Figure 3.9

Mounting studs

Carburetor gasket

Figure 3.10

Throttle arm

Governor rod

2j. Lift the Autochoke Air Vane off of the its pivot. 2k. Unhook the choke rod from the carburetor.

See Figure 3.8.

2l. If the engine is not equipped with an auto-

choke, remove the carburetor gasket.

2m. Slide the carburetor off of the mounting studs.

See Figure 3.9.

2n. Rotate the throttle arm until it meets the idle

speed screw, then pivot the carburetor slightly to disengage the 90 degree bend at the end of the governor rod. See Figure 3.10.

2o. Unhook the stabilizer spring that takes-up the

play between the governor arm, the governor rod, and the throttle arm on the carburetor.

AIR INTAKE SYSTEM

Figure 3.11

Carburetor Calibration Number

Figure 3.12

Suppler trademark

Alphanumeric code

Calibration code

Serial code

Figure 3.13

Gasket: insulator to cylinder head

Gasket: Insulator

to carburetor

Insulator

NOTE: The carburetors are not inter -changeable from one

engine model to another. To help prevent carburetor mix-ups, the Carburetor Calibration Number is stamped on the carburetor by the fuel nipple. Calibration numbers are similar or the same as the engine number. See Figure 3.11.

NOTE: MTD gets carburetors from several suppliers.

When ordering carburetor kits, the carburetor’s manufacturer, calibration code and serial number are needed. All of this information is located on the carburetor. See Figure 3.12.

3. The insulator is sandwiched between two gaskets which are located between the carburetor and the cylinder head. See Figure 3.13.

NOTE: The gaskets are different, and there is an orienta-

tion to the insulator.

NOTE: The front gasket also acts as a heat shield.

4. Install the insulator by following the above steps in reverse order.

NOTE: Tighten the carburetor mounting nuts to a torque of

80 - 106 in lbs (9 - 12 Nm).

5. Test run the engine before returning to service.

T65 Series Vertical Shaft Engines

FUEL SYSTEM AND GOVERNOR

Figure 4.1

NBR inner liner

THV barrier layer

NBR intermediate layer

Reinforcement

CSM Cover

Picture courtesy of Avon Automotive

When working around the fuel system, do not bring any source s of hea t, spark, or open flame near the work area.

! WA RNI NG! WA RNI NG

CHAPTER 4: THE FUEL SYSTEM AND GOVERNOR

The function of the fuel system is to store fuel, mix the fuel with air in the correct ratio and deliver it to the intake

port. The fuel system consists of the following components:

• Fuel tank

• Fuel lines

• Fuel filter

• Carburetor and insulator block NOTE: When working on the fuel systems, look at the whole system. A problem will rarely be isolated to one

component.

Fuel Line

The fuel line used by MTD is GREENBAR a multi-layer fuel line that meets the current EPA guidelines.

. This is

NOTE: This fuel line has a thin inner liner. If a tear

forms in this inner liner, fuel can get be tween the liner and the hose. This will cause the liner to collapse, cutting off the fuel flow.

NOTE: The fuel line must be replaced every time it

is disconnected from the brass barb on the carburetor.

NOTE: Replace the fuel line only with GREEN-

BAR

Inspect the fuel lines

• Are they cracked?

• Are they clogged?

• Are they brittle? NOTE: If the answer to any of the above is yes,

replace the fuel lines. When replacing fuel lines, GREENBAR order to meet EPA and CARB standards.

700 series fuel line.

700 series fuel line must be used in

NOTE: The carburetor nipple has a sharp edge that will damage the inner lining of the fuel line. Replace the

fuel line every time it is removed from the nipple.

• Drain the fuel tank or clamp the fuel line before starting work to preven t sp illa g e.

• Dispose of drained fuel in a safe and responsible manner.

T65 Series Vertical Shaft Engines

Figure 4.2

Figure 4.3

Inspecting the fuel

NOTE: Fuel is the maintenance item most often overlooked by consume rs. A lot of f uel systems prob lems are

caused by gas that is out of date or fuel with too much alcohol in it. When inspecting the fuel:

• Look for water.

• Look for dirt.

• Look for discoloration.

• Sniff carefully to see if it smells like varnish or kerosene.

• Look for oil in the fuel.

• Test the fuel for alcohol content.

NOTE: Save a sample of the fuel collected to show the customer. NOTE: Customers pouring engine oil into the fuel tank seems to be a growing problem.

Test fuel for alcohol

Fuels currently on the market contain a wide array of additives. Some of these additives oxygenate the fuel. Oxygenated fuel reduces emissions, and is required in some parts of the United States. Fuel make-up varies seasonally and geographically. Ethanol is the primary additive used to oxygenate fuel.

Ethanol in fuel creates a lot of problems for gasoline engines. The biggest problem is that alcohol attracts and holds water. This corrodes the metal components of the fuel system, especially the carburetor. Alcohol also does not produce as much heat as gasoline when burned and it burns at a different stoichiometric ratio. This results in less power for the engine.

A 10% ethanol (E10) mix is acceptable for MTD engines. Anything higher than that will result in performance issues and is not covered by warranty.

NOTE: E15 and E85 fuels are not to be used in any

MTD engines.

There are several alcohol test kit available commercially. See Figure 4.2.

Generally these kits involve mixing a measured amount of water and gas together and seeing were the boundary layer is. See Figure 4.3.

The test kit should come with a chart to compare the boundary layer height to alcohol percentage.

The fuel filter

Figure 4.4

Figure 4.5

Charcoal canister fuel cap

Evaporative (EVAP) emissions system

FUEL SYSTEM AND GOVERNOR

The fuel filter is located in the fuel tank. It can be remo ve d and cleaned with a can of carburetor cleaner or replaced. See Figure 4.4.

Gasoline is made from the graduated distillation of crude oil. It consists of a multitude of individual hydrocarbons and has a boiling range of 86 - 410

gasoline an ideal fuel for spark ignited, internal combustion eng ines. However, the hydrocarbons are not good for the environment. To reduce or eliminate the release of fuel vapors into the atmosphere, an evaporative (EVAP) emissions system is used. St arting with the 2008 season, an EVAP system has been offered in areas that require it. MTD uses a charcoal canister fuel cap on the T65 series engines.

NOTE: All fuel caps must be tethered to the fuel tank as part of the EPA Tier III emissions. A broken tether on

the fuel cap must be repaired before the unit can be put back into service.

Charcoal canister fuel caps

F (30-210oC)1. The large quantity of hydrocarbons and the low boiling range makes

The simplest and most common EV AP system used on an MTD engines is the charcoal canister fuel cap. The fuel cap has charcoal that will absorb most of the vapors that try to escape through the vent.

When the engine is running and the fuel level drops, a vacuum is created. The clean air that is drawn in through the vent will pull the vapors out of the charcoal, refreshing it for the next cycle.

A charcoal canister fuel cap can be identified by its height. See Figure 4.5.

1. Dr. Ullmann, J, Fuels, Automotive Ha ndbook, seventh edition. Bosch, Robert distributed by SAE Society of Automotive Engineers, 2007. 320.

T65 Series Vertical Shaft Engines

Figure 4.6

Vent hole

Figure 4.7

Hand-pump vacuum

/pressure tester

Fuel tank vent

The fuel tank vent performs the important task of allowing air into the fuel tank. As fuel is being used by the engine, the fuel level in the tank drops. The dropping fuel level then creates a vacuum in the tank. If the fuel tank could not allow air through the vent, the vacuum would prevent the fuel from getting to the carburetor.

The tank is vented through the cap. See Figure 4.6.

NOTE: This is a charcoal canister fuel cap. If the

vent is not functioning, the whole fuel cap must be replaced.

To test the cap vent:

1. Drain the fuel out of the fuel tank into an approved

container.

2. Attach a hand-pumped vacuum/pressure tester to

the fuel barb on the fuel tank. See Figure 4.7.

3. Attempt to pull a vacuum on the fuel tank with the

fuel cap in place.

4. Attempt to pressurize the fuel tank with the fuel cap

in place. NOTE: The tank should not hold any pressure nor

any vacuum.

• Replace the cap if either pressure or vacuum builds using the hand-pump tester.

• A cap that maintains pressure will cause the engine to run rich as the fuel in the tank heats and expands, forcing it’s way past the float valve in the carburetor.

• A cap that maintains vacuum will cause the engine to run lean as the fuel is depleted and no air comes in to replace it.

• The two conditions may both be present, but the symptoms vary with fuel, fuel level, and operating conditions.

• Usually presents as a “Runs and quits” scenario.

The fuel tank

When working around the fuel system, do not bring any source s of hea t, spark, or open flame near the work area.

! WA RNI NG! WA RNI NG

Figure 4.8

Tether

Figure 4.9

Gland nut

Rubber washer

FUEL SYSTEM AND GOVERNOR

To remove the fuel tank:

1. Drain the fuel out of the fuel tank into an approved container.

2. Disconnect the fuel line from the tank.

3. Remove the recoil starter by following the procedures described in Chapter 6: Starters

4. Lift the blower housing off of the engine.

5. Remove the fuel cap and tether by unscrewing them. See Figure 4.8.

6. Remove the fuel tank gland nut.

7. Remove the rubber washer.

8. Slide the tank out of the blower housing.

9. Install the fuel tank by following the previous step in reverse order.

T65 Series Vertical Shaft Engines

Figure 4.10

Choke closed

Air vane

Figure 4.11

Choke

open

Air flow

Figure 4.12

Temperature compensator

Choke Compensator rod

Autochoke

The MTD engine uses a simple autochoke system that is similar to the old style air vane governors. When the engine is at rest a spring holds the choke in the closed position. See Figure 4.10.

When the engine starts, the air flow from the flywheel fan pushes on an air vane. The air vane in turn moves the choke lever, opening the choke. See Figure 4.11.

The Autochoke System also has a temperature compensator installed on the muffler . As the muffler heat s up, a bi-metallic coil inside will expand. The expanding coil will rotate a lever towards the muffler , pulling on a rod. This rod will override the autochoke, holding the choke open on hot restarts. It will also keep the choke from fully closing until the engine heats up.

Temperature compensator

Figure 4.13

Air Vane

Figure 4.14

Temperature Compe nsa to r

Choke rod

FUEL SYSTEM AND GOVERNOR

To remove/replace the air vane:

1. Unplug the spark plug.

2. Drain the fuel out of the fuel tank into an approved container.

3. Disconnect the fuel line from the tank.

4. Remove the recoil starter by following the procedures described in Chapter 6: Starters

5. Lift the blower housing off of the engine.

6. Lift the air vane off of the bracket. See Figure 4.13.

7. Unhook the choke linkage.

8. Install by following the above steps in reverse order.

To remove/replace the temperature compensator:

1. Remove the muffler cover by following the p rocedures described in Chapter 8: Exhaust.

2. Remove the two screws that hold the compensator to the muffler using a 10 mm wrench. See Figure 4.14.

3. Unhook the compensator from the choke rod.

4. Install the compensator by following the previous steps in reverse order.

T65 Series Vertical Shaft Engines

Figure 4.15

Primer

Carburetor

Air pressure

Figure 4.16

Choke is removed

Primer port

Figure 4.17

Remove the

primer line

Primer

Another way to enrichen the fuel air mixture for startup is the primer. The primer is a simple pump that pressurizes the float chamber, forcing fuel out the main nozzle. See Figure 4.15.

Carburetors that use a primer are ea sily ide n tifie d by the lack of a choke plate and the addition of a primer port. See Figure 4.16.

To remove/replace the primer:

1. Remove the air filter housing by following the steps

described in Chapter 3: Air Intake And Filter.

2. Disconnect the primer line from the primer bulb. See

Figure 4.17.

FUEL SYSTEM AND GOVERNOR

Figure 4.18

Squeeze the barbs together,

then push

3. Squeeze the two sets of tabs together and push the primer out of the housing. See Figure 4.18.

4. Install the primer by following the above steps in reverse order.

5. Test run the engine before returning to service.

Carburetors

Troubleshooting the carburetor is a process of elimination. If everything else on the engine checks out, the carbu-

retor is probably bad.

NOTE: It is important to perform a compression or leak down te st befor e conde mnin g a car bur etor. An engine

can have a borderline compression reading and not create enough of a vacuum to draw in a sufficient fuel/air charge.

NOTE: If the engine has border-line compression, a quick test to see if that is the problem is to remove the

spark plug. Squirt a little bit of oil into the combustion chamber to seal the rings. Reinstall the spark plug. If the engine starts and runs ok, then that was the pr oblem. If it does not st art, move on to the carburetor.

Inspecting the carburetor:

1. Remove the float bowl and check for dirt and/or varnish.

2. Inspect the needle valve and needle valve seat for dirt and/or damage.

3. Inspect the gaskets and O-rings for damage.

4. Inspect the vents and orifices, verify that they are free of debris. NOTE: If a little cleaning and new gaskets will fix the carburetor, do it. If the carburetor requires extensive

cleaning it is better to replace the carburetor.

IMPORTANT: Never try to mechanically clean orifices. That will damage them and ruin the carburetor. NOTE: The carburetors used on all vertical shaft engines are similar in design, but differ in calibration. NOTE: The jet markings (if present) may be used for identification purposes, but the technician should not

attempt to infer orifice sizes from the identification numbers.

NOTE: Installing the wrong main jet, or a carburetor with the wrong main jet will produce performance and

emissions issues.

T65 Series Vertical Shaft Engines

Figure 4.19

Bowl vent port

Bowl vent channel

Figure 4.20

Float bowl Drain bolt Flat fiber

gasket

Bowl bolt

Gasket seal

Figure 4.21

Float

Float pin Float valve

Fuel inlet

Disassembly and rebuilding the carburetor

1. Clamp off the fuel line to prevent fuel spillage and remove it.

2. Remove the carburetor by following the steps described in Chapter 3: Air Intake and Filter.

NOTE: There is a corresponding passage recessed into the mating surface where the throttle end of the carburetor housing meets the gasket. See Figure

4.19.

3. Remove the bowl bolt using a 10mm wrench. See

4. Remove the pin that the float hinges on to remove

Figure 4.20. NOTE: From this point an assessment can b e made

about the viability of rebuilding the carburetor.

• If extensive corrosion is evident, replace the

carburetor.

• If varnish build-up is too extensive to clean,

replace the carburetor.

the float. See Figure 4.21.

FUEL SYSTEM AND GOVERNOR

Figure 4.22

Float Compression

spring

Float valve

Figure 4.23

Main jet Bowl gasket

Bowl vent port

Figure 4.24

Port for the primer

NOTE: The float is not adjustable. Spring tension against

the float valve begins to build from the horizontal position, putting progressively more pressure between the tip of the valve and the seat. See Figure 4.22.

NOTE: Because the float valve is crucial to the functioning

of the carburetor, and the Viton tip of the valve is subject to wear, it is suggested that technicians replace the valve and spring any time the carburetor is disassembled for cleaning.

• A square cross-section gasket seals the bowl to the body of the carburetor.

5. Remove the main jet by using a narrow-shank straight blade screwdriver. See Figure 4.23.

NOTE: A primer carburetor will have an additional port so

that the air from the primer bulb can enter the float chamber. See Figure 4.24.

T65 Series Vertical Shaft Engines

Figure 4.25

Bowl vent ports

Emulsion air port: main jet

Emulsion air port: pilot jet

Emulsion tube

Main jet

Figure 4.26

Welch plug

Fuel feed leg on central column for pilot and transition

shot plug in feed bore Fuel port to

central column

Throttle Stop Scre w

Figure 4.27

NOTE: Fuel enters the central column through a

port about 1/2” (1cm) from the bottom, to help prevent the ingress of any residue in the bottom of the bowl.

NOTE: The orifice in the main jet meters fuel into

the central column.

NOTE: Air from the main jet emulsion port enters

the central column near the top, then gets bubbled through the emulsion tube into the metered fuel flow to promote atomization.

NOTE: The main jet secures the emulsion tube in

the central column of the carburetor. See Figure 4.25.

6. The Throttle Stop Screw has a large pliable lip around the head of the screw. That lip secures a metering plug for the pilot and transition ports. Remove the screw to reach the plug. See Figure

4.26.

7. Carefully pry out the metering plug using a small screwdriver. See Figure 4.27.

FUEL SYSTEM AND GOVERNOR

Figure 4.28

O-ring seals

Air passage

End view

Fuel metering orifice

Figure 4.29

Idle Speed Screw

Figure 4.30

Governor guard

8. Examine the metering plug: See Figure 4.28.

• Fuel, drawn from the central column via the long fuel feed leg, is metered by the brass orific e in th e tip of the metering plug.

• Air, drawn fr om the emulsion air port, is metered by the size of the brass orifice at the entrance to the port.

• The fuel and air that feed the pilot and transition ports are mixed at the metering plug.

• The metering plug creates a small venturi. The pressure drop of the air passing throu gh the me tering plug draws the fuel into the passage to the pilot and transition ports, in an emulsified mixture.

9. Clean the carburetor body in an ultrasonic cleaner. NOTE: Traditional dips are not recommended.

10. Rinse thoroughly.

11. Dry the carburetor body using compressed air.

12. Pre-installation adjustment: 12a. Tighten the idle speed screw until 1/8” (3 mm)

of the screw is visible on the throttle arm side of the housing. See Figure 4.29.

13. Reassemble the carburetor and install it with a new fuel line, by following steps 1-8 in reverse order.

14. Remove the governor guard using a 10 mm wrench. See Figure 4.30.

T65 Series Vertical Shaft Engines

Figure 4.31

Digital tachometer confirms safe operating speed

Figure 4.32

Increase spring tension to increase engine speed

Decrease spring tension to decrease engine speed.

Tab

NOTE: For mower applications, the idle speed is

not normally critical because the operator is not provided with a throttle control.

15. Check the top no load speed of the engine. See Figure 4.31.

NOTE: The top no load speed should be 3200 */-

100 rpm.

16. Adjust the top no-load speed by slightly bending the tab that the governor spring conn ects to. See Figure

4.32.

Governor

Figure 4.33

Spring tension

Governor action

Figure 4.34

Nut and through bolt

Governor arm

FUEL SYSTEM AND GOVERNOR

The engine speed is controlled by a balance between the force applied by a spring (pulling the throttle open) and a flyweight mechanism within the engine applying force to the governor arm (pushing the throttle closed). See Figure

4.33. NOTE: While the mechanism is simple and robust, it is

important to pay attention when working on parts near the governor. Binding caused by interference with mis-routed lines or cables may make the governor unresponsive.

NOTE: When a governed engine “hunts”, it is gen erally an

indication of a lean fuel/air mixture, rather than a problem with the governor.

1. To remove the governor arm from the governor shaft:

1a. Unhook the governor spring. 1b. Loosen the nut and through bolt. See Figure

4.34.

1c. Make an index mark to orient the shaft to the

arm on installation, remove the arm and go to step 3.

1d. Carefully slide the Governor arm off of the

governor shaft.

1e. Unhook the governor linkage.

2. If the governor arm is being installed without bene fit of index marks:

2a. Rotate the governor shaft clockwise as far as it will go. 2b. Position the arm so that the throttle plate in the carburetor is at the wide open position.

3. Slide the arm onto the shaft. The flat on the top of the shaft should be roughly perpendicular to the shaft. NOTE: There is a hairpin clip that helps keep the governor shaft from sliding into the engine, however it only

rides on a grove and can pop off. It may be necessary to hold the shaft while sliding the arm on to pre vent it from going into the engine.

4. Tighten the nut on the clamp bolt to secure the arm. NOTE: Make sure to take the slack out of the system while tightening the clamp bolt.

5. Attach the govern linkage and spring.

6. Start the engine and check the top no load RPM using a tachometer.

7. Adjust the governor to maintain top no-load speed as described in a previous section of this chapter.

T65 Series Vertical Shaft Engines

Figure 4.35

Hair pin clip

Figure 4.36

Remove the governor shaft

Figure 4.37

Governor shaft seal

Governor shaft

To remove or replace the governor shaft:

1. Remove the engine from the unit.

2. Remove the governor arm by following the previously described steps.

3. Remove the sump by following the steps described in Chapter 10: Disassembly.

4. Remove the hair pin clip from the governor shaft. See Figure 4.35.

5. Slide the governor arm out of the engine block from the inside of the engine. See Figure 4.36.

6. Remove the governor shaft seal. See Fi gure 4.37.

FUEL SYSTEM AND GOVERNOR

Figure 4.38

Seal

Figure 4.39

Governor shaft must be perpendicular to the case

7. Slide the governor shaft through the engine block from the inside of the engine.

8. Carefully slide a new seal over the governor shaft and seat using a 1/4” deep well socket. See Figure

4.38.

9. Install the hair pin clip.

10. Rotate the governor shaft so that the bent end is be perpendicular to the case. See Figure 4.39.

NOTE: If the governor shaft is not pointing up while sliding

the sump on, the governor shaft will not catch the governor cup. This will prevent the governor from changing the engine rpm and usually presents as an over-speeding engine.

11. Install the sump by following the steps described in Chapter 10: Disassembly.

12. Rotate the governor shaft clockwise as far as it will go.

13. Position the top of the arm about 3/16” (.476cm) from the boss on the casting that provides a mounting point for the fuel tank bracket.

14. Install the governor arm by following the steps described in the previous section.

15. Install the engine on the unit.

16. Test run the engine and adjust the top no load engine RPMs by following the steps described in “Disassembly and rebuilding the carburetor” section of this chapter.

T65 Series Vertical Shaft Engines

Figure 4.40

Remove these screws

Figure 4.41

Governor gear

Governor cup

Gear shaft

Governor cup washer

Governor cup and the governor gear

1. Remove the engine from the unit.

2. Remove the sump by following the steps described in Chapter 10: Disassembly.

3. Remove the two screws that hold the governor gear plate to the sump using a 10mm wrench. See Figure

4.40. NOTE: Some models only have one screw. On the

single screw models, Inspect the plate for any deformity, discard if any is found.

4. Slide the gear shaft out of the gear and cup. See Figure 4.41.

5. Install by following the above steps in reverse order.

NOTE: Check the governor arm for freedom of

6. Test run the engine and adju st th e to p no load engine RPMs by following the steps described in “Disassembly and rebuilding the carburetor” section of this chapter.

movement before test running the engine.

Lubrication

SAE 40

SAE 30

SAE 10W30/SAE 10W40

SAE 5W20

-4°F

14°F

32°F 50°F 68°F 86°F 104°F

-20°C

-10°C

0°C

10°C 20°C

30°C

40°C

Oil Chart

CHAPTER 5: LUBRICATION

Oil type and quantity

The recommended oil for MTD engines is an SAE 10W-30 oil with an SM API rating or better. The oil capacity is

17.0- 20.3 fl.oz (0.5-0.6 liters).

• If the oil is noticeably thin, or smells of gasoline, carburetor repair may be needed before the engine can be run safely.

• Check the oil level frequently and change the oil more frequently in severe operating conditions such as exceptionally deep snow falls.

• Synthetic oil is a suitable alternative, but it does not extend service interva ls.

NOTE: MTD recommends the use of petroleum oil during the break in period to ensure the piston rings correctly break in.

Synthetic vs. Petroleum based oil: To simply look at synthetic oil and to com pare it with Petroleum based oil there is very little difference. However, when you look at the two through a microscope it is easy to see the difference . Synthetic is made up of smaller molecules. This allows the oil to get into areas that petroleum based oil cannot.

T65 Series Vertical Shaft Engines

Figure 5.1

1/4 turn

Threaded

Figure 5.2

Dip stick

Figure 5.3

Fully seat the dip stick before reading it

Oil dipstick

NOTE: There are two types of dip sticks that can be

found on MTD engines; a threaded dip stick that was used on older engines and a quarter turn dip stick that is used on engines currently being produced. See Figure 5.1.

To check the oil with a threaded dip stick:

1. Twist and remove the dip stick from the engine.

2. Clean the oil off of the tip of the dipstick.

3. Re-insert the dipstick without threading it in to get the oil level reading. See Figure 5.2.

4. The oil level is determined by the lowest point on the dipstick that is completely covered with oil.

To check the oil with a 1/4 turn dip stick:

1. Twist and remove the dip stick from the engine.

2. Clean the oil off of the tip of the dipstick.

3. Re-insert the dipstick and turn it until it is fully seated to get the oil level reading. See Figure 5.3.

4. The oil level is determined by the lowest point on

the dipstick that is completely covered with oil.

Dipstick tube removal

Figure 5.4

Dip stick tube

Screw

Figure 5.5

Lubrication

Some MTD engines come with a dip stick tube, depending on the application. See Figure 5.4.

To remove/replace the dip stick tube:

1. Remove the dip stick.

2. Remove the screw at the to p of th e dip stick tu be . See Figure 5.4.

3. Pull the dip stick tube out of the engine block.

4. Inspect the O-rings on the dip stick and the dip stick tube. Replace if damaged. See Figure 5.5.

5. Install by following the previous steps in reverse order.

T65 Series Vertical Shaft Engines

Figure 5.6

Governor gear

Paddles

Figure 5.7

Figure 5.8

Oil Return Port

Lubrication system

MTD uses a splash lube system for it’s vertical shaft engines. The governor gear has paddles on it that “splashes” oil around the inside of the engine. See Figure

5.6.

The splashing action will also atomize or change the oil into a mist. There are two oil passages that run along the engine cylinder. The one on the top side of the engine is the oil supply passage. The oil mist will flow through this passage to the cylinder head. The supply passage lines up with the top crank arm so that some of the oil on the crank arm will be flung into the supply passage, forcing additional oil up to the cylinder head. See Figure 5.7.

The second oil passage runs along the bottom side of the cylinder. This is the oil return passage. As the name implies, it allows the oil collecting in the cylinder head to return to the sump. See Figure 5.8.

NOTE: Because these engines use splash lubrica-

tion, the type of oil and the oil level is critical for proper operation of the engine. If the oil

level is too low, the p addle s on th e governor gear can not splash the oil into the engine. If the oil level is too high, the oil will not change into a mist to reach the upper side of the engine.

PCV

Figure 5.9

Autochoke Air Vane

Figure 5.10

PCV chamber cover

Dimple

Breather hose

Figure 5.11

Disc

Spring

Lubrication

The function and test procedures for the PCV is covered in Chapter 2: Basic Troubleshooting.

To service the PCV: NOTE: If the engine is equipped with an autochoke, lif t the

Autochoke Air V ane off of the PCV Chamber Cover Screw, and set it off to the side of the engine.

1. Remove the ignition module by following the steps described in the Chapter 7: Ignition System.

2. Remove the screw that hold the PCV Chamber Cover to the engine block using a 10mm wrench. See Figure 5.10.

3. The cover and gasket can be separated from the chamber. See Figure 5.11.

NOTE: The dimple in the cover helps locate the fiber disc

over the port that leads into the crankcase.

4. Inspect the disc for any signs of dirt, damage or leaking.

T65 Series Vertical Shaft Engines

Figure 5.12

Drain-back port

Breather tube

5. Inspect the oil drain-back port. Make sure it will allow oil to drain back into the engine. See Figure

5.12.

6. Reassemble the PCV.

7. Tighten the cover bo lts to a torque of 27 in-lbs. (3 Nm).

8. Inspect the breather tubing for cracks, brittleness or signs of leaking. Replace the breather tube if any are found.

9. Re-assemble the engine by following the above steps in reverse order.

10. Te st ru n th e en gin e befo re returning to service.

Recoil Starter Removal

Figure 6.1

Starters

CHAPTER 6: STARTER AND CHARGING SYSTEMS

To remove the recoil assembly from the engine:

1. If the engine is installed on a mower, loosen the wingnut that secures the starter rope eyelet to the handlebars enough to provide clearance for the star ter rop e and slide the rope out. Allow the starter rope to retract into the starter.

2. Remove the three nuts that secure the recoil assembly and the blower housing to the engine using a 10mm wrench. See Figure 6.1.

3. Lift the recoil assembly off of the engine.

4. Install the starter by following the previous steps in reverse order.

5. Test run the engine in a safe area before returning it to service.

T65 Series Vertical Shaft Engines

Figure 6.2

Starter cord

knot

Figure 6.3

Spring clamp maintains tension while rope is installed

Press knot fully into groove

Inset: knot

Figure 6.4

Starter Rope

The most common failure mode for most recoil assemblies is a broken rope. See Figure 6.2.

NOTE: If the spring was not damaged when the

recoil sprung back, It is possible to simply remove the remnants of the old rope.

1. Remove the starter by following the step s described earlier in this chapter.

2. Remove the old starter rope by prying out the st arter cord knot and pulling the rope out with it.

3. Cut a piece of #4 recoil rope 9’ (3 meters) long.

4. Heat fuse the ends of the starter rope, and tie a double half-hitch in one end.

5. The rope may be easily installed from the insideout. Pull the rope tight to seat the knot firmly in the recess in the back of the pulley. See Figure 6.3.

6. Wind the spring completely . Then rel ieve it minimum

7. Install the handle and handle insert on the loose end

8. Remove the spring clamp and carefully let the rope

9. Give the starter a couple of test pulls to verify the

1 full turn, counting when the pulley knot aligns with the rope bushing in the housing. (This usually results in about 1.5 - 1.75 complete turns of relief), and secure it with a spring clamp. See Figure 6.3.

of the rope, again using a double half-hitch. See Figure 6.4.

rewind into the starter.

right amount of tension on the starter rope.

Starters

Figure 6.5

Rope-return tension may be increased by winding the rope and pulley counter clockwise.

NOTE: If starter rope tension needs to be adjusted, there

is room between the recoil housing and the pu lley to wind-on more tension. See Figure 6.5.

10. Install the starter and tighten the starter nuts to a torque of 80 - 106 in lbs (9 - 12 Nm).

T65 Series Vertical Shaft Engines

Eye protection should be worn if the starter pulley is to be removed.

! CA UTION! CA UTION

Figure 6.6

Figure 6.7

Pressure plate

Shoulder screw

Starter pulley and recoil spring

The recoil spring is nested within the starter pulley and both parts are assembled as a single part number.

If damage is suspected, the recoil may be disassembled by:

1. Remove the starter by following the step s described earlier in this chapter.

2. De-tension the recoil spring: 2a. Pull the starter rope out part way 2b. Hold the pulley in place by either clamping it

with a spring clamp or tying a knot in the rope to prevent it from retracting into the starter as

shown in Figure 6.6. 2c. Push the rope out of the starter handle. 2d. Untie the knot. 2e. Slide the handle off of the rope. 2f. Carefully allow the rope to retract into the

starter.

3. Remove the shoulder screw and pressure plate using a 10 mm wrench. See Figure 6.7.

Starters

Figure 6.8

Torsion spring

L-shaped arm goes outside of the starter pawl, on installation

Figure 6.9

Pulley Spring Housing

Lithium grease

Eye protection should be worn if the starter pulley is to be removed.

The recoil spring is under tension

and can release as the pulley is removed.

! CAUTION! CAUTION

NOTE: Beneath the pressure plate is a compression

spring, and two starter pawls that are held in the disengaged position by two torsion springs.

4. Inspect the pawls and torsion springs for wear and damage. See Figure 6.8.

5. Carefully lift the spring and pulley out of the recoil housing. See Figure 6.9.

NOTE: If the spring is undamaged, but has been removed

from the pulley, the spring may be re-wound. Engage the hook in the end of the spring with the slot in the outer lip of the recess that the spring fits in, and wind the spring into the recess in a counterclockwise direction.

NOTE: Evaluate the damage, including parts prices and

local labor rates. In some parts of the country, it makes economic sense to replace the complete assembly, in other areas labor rates favor repair.

6. To re-assemble, apply a small amount of lithium-based chassis grease to the surface of the recoil h ousing that contacts the spring.

7. Carefully position the pulley and spring in the recoil housing. Rotate the pulley gently counter-clockwise until

8. Install the torsion springs and pawls so that the long arm of th e spri ng reache s outside of the pawl, and draws

the spring seats, allowing the pulley to fall into position.

it toward the center of the assembly. See Figure 6.10.

T65 Series Vertical Shaft Engines

Figure 6.10

Pressure Plate

Compression Spring

Pawl

Torsion Spring

NOTE: The rolled end of the pawl fits in the recess

in the starter pulley. T h e ho o ked en d engages the starter cup. Both the roll and the hook face inward.

NOTE: The extrusions on the pressure plate should

fall inside of the pawls as the starter is assembled.

NOTE: Drag on the pressure plate, from the friction

between the compression spring and the head of the shoulder screw causes these extrusions to force the pawls outward, engaging the starter cup.

9. Apply a small amount of thread locking compound such as Loctite 242 (blue) to the threads of the shoulder screw, a nd install the screw. Tighten it to a torque of 71 - 89 in lb. (8 - 10 Nm).

10. Install the starter rope by following the steps described in the previou s section of this chapter.

11. Install the starter and tighten the starter nuts to a torque of 80 - 106 in lbs (9 - 12 Nm).

Troubleshooting the ignition system

Figure 7.1

Spark tester

! CAUTION! CAUTION

Never remove the spark plug and hold it against the cylinder head to test for spark. The fuel/air mix com-

ing out of the spark plug hole will catch on fire.

Ignition System

CHAPTER 7: IGNITION SYSTEM

The purpose of the Ignition System is to provide a spark in the combustion chamber at the proper time to efficiently ignite the fuel/air mixture. The steps in troubleshooti ng the Ignition System are:

1. Examine the spark plug(s) by following the steps described in the spark plug section of this chapter.

NOTE: When the spark plug is removed, it is a good idea

to check the compression.

2. Connect a spark tester between the spark plug wire and a good ground point on the engine. See Figure 7.1.

NOTE: Do not connect the spark tester to the spark plug

when testing for ignition.

NOTE: It only takes 1,000 volts to jump a 0.025” a ir gap in o pen atmo sp her e, it takes 10,000 volts to jump the

same gap at 120 psi; therefore, an open air spark test is not valid.

NOTE: The spark should be a minimum of 10 Kv (10,000 volts) at pull over speed.

3. Move the throttle lever to the full throttle position. (if equipped)

4. Squeeze the safety bail (if equipped), and pull the starter rope. If sparks ca n be seen in the spark tester, the ignition system is working.

NOTE: If there are sparks present in the spark tester, install a known-good spark plug and prime test the

engine. If the engine does not start, check the fly wheel key. If the fly wheel key is intact, the problem is not in the ignition system. Check the engine’s compression.

5. If no sparks or weak sparks are seen in the spark tester, check the module air gap. NOTE: If the module air gap is correct, further testing is required.

6. Unplug the wire that connects the ignition module primary windings to a grou nd fo r eng ine shut down (the connector is behind the dipstick tube).

7. Re-test for sparks.

• If there are no sparks, the module is bad or the flywheel magnets have lost their magnetism (very rare).

• If there are sparks, troubleshoot the stop switch.

T65 Series Vertical Shaft Engines

Figure 7.2

Stop Switch

Contact

Figure 7.3

Ground connection

Stop switch connection

Safety bail in OFF position

Figure 7.4

Safety bail in

ON position

Troubleshooting the Stop Switch

To access the stop switch:

1. Drain the fuel out of the fuel tank into an approved container.

2. Disconnect the fuel line from the tank.

3. Remove the recoil starter by following the procedures described in Chapter 6: Starters

4. Lift the blower housing off of the engine. NOTE: The stop switch is mounted to the Engine

Brake See Figure 7.2.

To test the stop switch:

4a. Locate the wire from the primary windings of

the Ignition Module and disconnect it from the stop switch. See Figure 7.2.

4b. Connect an Ohm meter between the terminal

and a ground point. The reading should approach zero when the bail is released or the switch is turned off, closing the contacts. See Figure 7.3.

NOTE: If the reading is high, the contact may be

burnt or there is a bad ground to the switch. This could prevent the engine from shutting down rapidly.

4c. The reading should show no continuity when

the bail is pulled down. See Figure 7.4.

NOTE: If the reading shows continuity, the module

is shorted to ground and may not produce a spark. The wire will need to be traced back to the module to find the short.

Troubleshooting the Module

Figure 7.5

Inexpensive spark gap tester provides usable information

Figure 7.6

Instructions on back of package

Figure 7.7

1 reticle = 4,000 Volts waveform is 3 reticles tall

Ignition System

• Normal performance of the coil is to produce at least 10,000 volts at starter-rope pull-through speed. See Figure 7.5.

NOTE: Presence or absence of strong sp ark, with the stop

switch and wire known to be good, is generally enough to identify the ignition coil as good or bad. Resistance readings may help confirm the source of the failure, but are generally meaningless because they only measure a small part of the module.

NOTE: Presence of a weak spark maybe the result of an

improper air gap. The air gap space should be

0.012” - 0.020” (0.3 - 0.5 mm).

NOTE: Simple spark-testers are readily available and

inexpensive. Thexton Part # 404 is available from a variety of retailers, and similar unit s are available form other manufacturers. See Figure 7.6.

• At operating speed, the ignition should produce a spark approaching 12,000 V. See Figure 7.7.

T65 Series Vertical Shaft Engines

Figure 7.8

Pull-over speed: waveform is half-way between 2nd and 3rd reticle (10,000 V.)

Figure 7.9

Probe to laminations

Probe to wire to

stop switch

Figure 7.10

Probe to spark plug terminal

Probe to laminations

• At pull-over speed (~ be at least 10,000V. See Figure 7.8.

NOTE: Flash-over voltage will vary with spark plug

condition and gap.

NOTE: Pull-over speed may vary from operator to

operator.

To measure the resistance of the module’s windings:

1. Set a Digital Multi-Meter (DMM) to read resistance.

2. Connect the one lead to the module’s laminations.

3. Disconnect the Stop Switch.

600 RPM), voltage should

4. Connect the other lead of the DMM to the wire from the module that was disconnected from the Stop Switch. See Figure 7.9.

5. Resistance in the primary windings of the ignition module, measured between the spade ter minal and the laminations.

NOTE: The reading should be in the 1.0 - 2.0 

range.

6. Move the probe from the wire to the Stop Switch to the spark plug wire. See Figure 7.10.

NOTE: The reading should be in the 5 K - 7 K

• There may be slight variation in specification

• Resistance figures that are vastly lower may

• Resistance figures that are vastly higher (or

range.

due to production variation and other factors such as temperature.

indicate a short in the windings being tested.

OL) may indicate a fault in the windings being tested.

Ignition System

Figure 7.11

Magnets

NOTE: Intermittent failure requires tests for voltage

and resistance to be made when the engine is cold, and again when it is hot. Typical customer complaint: “It stops after I mow for 10 minutes and I can’t get it to re-start”.

• To confirm that the problem is ignition-based, it is necessary to “catch it in the act”.

• Resistance normally increases slightly as temperature increases.

NOTE: Failure of the magnets in the flywheel is

exceedingly rare. To test the magnets, simply hold an item made of ferrous metal roughly 1/4” (6.35 mm) away from the magnets in the flywheel. It should be drawn to the flywheel. A wrench or screwdriver is suitable for this test.

NOTE: An inexpensive compass or bar magnet can be used to confirm opposite polarity of the flywheel mag-

nets. See Figure 7.11.

7. Inspect the flywheel. The flywheel is a frequently forgotten component of the ignition system. It holds the magnets that induce a field in

the module which in turn produces a spark. But it also controls the timing of the ignition system by controlling when the magnets are introduced to the module.

A sheared flywheel key will throw off the ignition timing. To inspect the flywheel and key:

1. Remove the recoil assembly by following the steps describe in Chapter 6: Starter.

2. Remove the flywheel by following the steps described in the flywheel section of this chapter.

3. Inspect the flywheel key and the key way on the crank shaft.

NOTE: If the flywheel key is damaged, replace it. If the keyway on the crankshaft is damaged, the engi ne must

be short blocked.

T65 Series Vertical Shaft Engines

Figure 7.12

Spark Plug

High tension lead

About the spark plug

• The Spark Plug is a F5RTC, part #951-14437, gapped to 0.024” - 0.031” (0.6 - 0.8 mm).

• Wear rate will vary somewhat with severity of use. If the edges of the center electrode are rounded-off, or any other apparent wear / damage occurs, replace the spark plug before operating failure (no start) occurs.

Cleaning the spark plug

• Cleaning the spark plug is not recommended. If the plug needs to be cleaned, replace it.

• Use of a wire brush may leave metal deposits on the insulator that cause the spark plug to short-out and fail to spark.

• Use of abrasive blast for cleaning may damage the ceramic insulator or leave blast media in the recesses of the spark plug. When the media comes loose during engine operation, severe and non-warrantable engine damage may result.

Inspection of the spark plug

Inspection of the spark plug can provide indications of th e op er a ting con d ition of th e en gin e .

• Light tan colored deposits on insulator and electrode s is nor mal.

• Dry , black deposits on the insulator and electrodes indicate an over-rich fuel / air mixture (too much fuel or not enough air)

• Wet, black deposits on the insulator and electrodes indicate the presence of oil in the combustion cham-

• Heat damaged (melted electrodes / cracked insulator / metal transfer deposits) may indicate detonation.

• A spark plug that is wet with fuel indicates that fuel is present in the combustion chamber, but it is not

Spark plug removal

1. Disconnect and ground the spark plug wire.

2. Remove the spark plug using a 13/16” or 21mm wrench. See Figure 7.12.

3. Gap a new spark plug to 0.024” - 0.031” (0.60 - 0.80 mm).

4. Install the new spark plug and tighten to a torque of 15 - 18.5 ft lbs (20 - 25 Nm).

ber.

being ignited.

Ignition Module

Figure 7.13

Ignition Module

Stop Switch

Figure 7.14

0.012” feeler gauge

Figure 7.15

Magnets

Ignition System

To removal an Ignition Module:

1. Unplug the spark plug.

2. Drain the fuel out of the fuel tank into an approved container.

3. Disconnect the fuel line from the tank.

4. Remove the recoil starter by following the procedures described in Chapter 6: Starters

5. Lift the blower housing off of the engine.

6. Unplug the wire from the spade terminal on the Stop Switch.

7. Remove the module using a 10 mm wrench.

To install an ignition module and set the air gap: NOTE: If just setting the air gap, loosen the module

mounting screws first then follow the same steps as described below.

1. Rotate the flywheel so that the magnets are away from where the module is mounted.

2. Install the module. Do not tighten the module down.

3. Place a non-ferrous feeler gauge between the module and the flywheel. See Figure 7.14.

NOTE: The air gap should be 0.012” - 0.020” (0.3 - 0.5

mm).

4. Rotate the flywheel so that the magnets align with the legs of the module while holding the feeler gauge in place. See Figure 7.15.

5. Tighten the module mounting screws to a torque of 89 in lbs (10 Nm).

6. Rotate the flywheel to remove the feeler gauge.

7. Install the blower housing and starter.

8. Connect the spark plug wire to the spark plug.

9. Test run the engine before returning to service.

T65 Series Vertical Shaft Engines

Figure 7.16

Releasing the engine control

cable from the bracket

Figure 7.17

Remove these bolts

Engine brake and stop switch (if equipped)

The stop switch and brake (for lawn mower applications) must be able to stop the blade from rotating within 3.0 seconds after the release of the safety bail, per ANSI B71.1-2003 standard.

NOTE: The brake should be replaced w he n the th ickn ess of the pad is less than 0.25” (6.35 mm) at the thin-

nest spot.

To replace the brake assembly:

1. Unplug the spark plug.

2. Drain the fuel out of the fuel tank into an approved container.

3. Disconnect the fuel line from the tank.

4. Remove the recoil assembly by following the steps described in Chapter 6: Starter.

5. Lift the blower housing off of the engine.

6. Remove the engine control cable by: 6a. Unhook the Z-fitting from the brake assembly. 6b. Squeeze the barbs together at the engine end

of the cable housing and push it through the brake assembly. See Figure 7.16.

7. Disconnect the connector in the lead that goes to the module.

8. Remove the two bolts securing the brake assembly. See Figure 7.17.

9. Install the brake assembly by following the previous steps in reverse order.

10. T est run the engine in a safe area before returning it to service.

Flywheel

Figure 7.18

A couple of threads past the end of the crank shaft

Figure 7.19

Engine Brake

Figure 7.20

Brass Punch

Ignition System

To remove the flywheel:

1. Unplug the spark plug.

2. Drain the fuel out of the fuel tank into an approved container.

3. Disconnect the fuel line from the tank.

4. Remove the recoil starter by following the procedures described in Chapter 6: Starters

5. Lift the blower housing off of the engine.

6. Loosen the flywheel nut until it is a couple of threads past the end of the crank shaft using a 19 mm wrench. See Figure 7.18.

7. Clamp off the engine brake. See Figure 7.19.

8. Remove the flywheel by applying a sharp blow to the crankshaft using a brass drift punch and a hammer while gently prying with a prybar. The flywheel will “pop” loose then lift it off.

NOTE: Never strike the crankshaft directly with a hammer.

To prevent damage to the crankshaft use a brass drift punch or a piece of wood between the hammer and the crankshaft. See Figure 7.20.

T65 Series Vertical Shaft Engines

Figure 7.21

Key flat parallel to the threads

Taper

! CA UTION! CA UTION

If the flywheel shows any signs of physical damage such as cracks, bro-

ken vanes (if equipped), or a damaged keyway, replace it. A damaged flywheel poses a threat of a burst failure. Burst failures are extremely hazardous to surrounding people and property.

9. Inspect the key, keyway, and tapered mating surfaces of the flywheel and crankshaft. See Figure

7.21. NOTE: If the key is damaged it must be replaced. If

there is damage to the crankshaft key way, the engine must be short blocked because crankshafts are not available as a service part.

10. On installation, confirm that the key is properly seated (the flat of the key parallel with the threaded section of the crankshaft) in the key-way, and that the tapers are fully seated. Key or keyway failure may result from improper seating.

IMPORTANT: The taper in flywheel and the on the crankshaft must be clean and dry. The flywheel is held in

place by the friction fit between the flywheel and the crankshaft, not the key. The key is only to guide the flywheel to the proper position until it is torqued down.

11. Install the flywheel nut to a torque of 47 - 52 ft lbs (64 - 70 Nm).

12. Adjust the air gap by following the steps described in the previous section of this chapter.

13. Reassemble the engine.

14. Te st ru n th e en gin e befo re returning to service.

Exhaust

Figure 8.1

Figure 8.2

Temperature compensator

CHAPTER 8: EXHAUST

Muffler

The exhaust system is a frequently overlooked component of an engine. It is important to make sure the muffler

is in good condition and free of debris and/or insects.

NOTE: A blocked muffler will result in poor performance. If a muffler is completely blocked the engine may not start.

To remove/replace the muffler

1. Unplug the spark plug.

2. If the engine does not have an Autochoke Temperature Compensator, skip to step 7.

3. Drain the fuel out of the fuel tank into an approved container.

4. Disconnect the fuel line from the tank.

5. Remove the recoil starter by following the procedures described in Chapter 6: Starters

6. Lift the blower housing off of the engine.

7. Remove the two muffler nuts. See Figure 8.1.

8. Slide the muffler cover off of the engine.

9. Disconnect the Autochoke Temperature Compensator, if equipped, using a 10 mm wrench.

T65 Series Vertical Shaft Engines

Figure 8.3

Muffler

10. Slide the muffler off of the studs. See Figure 8.3. NOTE: The exhaust gasket is made of a graphite

material. It will stick to the sealing surfaces when pressure is applied, tearing when pressure is relieved. The gasket can only be used one time.

11. Clean the cylinder head and muffler of any residual gasket material.

12. Using a new gasket, install the muffler by following the above steps in reverse order.

NOTE: Tighten the muffler nuts to a torque of 80 -

106 in lbs (9 - 12 Nm).

13. Te st ru n th e en gin e befo re returning to service.

Cylinder Head

Figure 9.1

Figure 9.2

Valve cover

screws

Spark plug

Cylinder head

CHAPTER 9: CYLINDER HEAD

The Cylinder head of the MTD engine can be removed without removing the engine from the application.

To remove the cylinder head: NOTE: If possible, It is recommended that the machine be

positioned on the bench so that the cylinder head is vertical for removal. See Figure 9.1.

NOTE: This position provides easy a ccess to most service

points, yet prevents undue oil spillage.

1. Remove the spark plug.

2. Drain the fuel out of the fuel tank into an approved container.

3. Disconnect the fuel line from the tank.

4. Remove the recoil starter by following the procedures described in Chapter 6: Starters

5. Lift the blower housing off of the engine.

6. Remove the carburetor and insulator by following the procedures described in Chapter 3: Air Intake System.

7. Remove the muffler by following the procedures described in Chapter 8: Exhaust.

8. Remove the four screws that secure the valve cover using a 10mm wrench, and remove the valve cover from the engine. See Figure 9.2.

NOTE: If care is used not to damage the valve cover gas-

ket, it can be re-used.

T65 Series Vertical Shaft Engines

Figure 9.3

Jam nut

Fulcrum nut

Figure 9.4

Figure 9.5

Alignment dowels

9. Loosen the jam nuts and fulcrum nuts that secure the rocker arms using a 10mm wrench and a 14mm wrench. See Figure 9.3.

10. Pivot the rocker arms aside, or remove them completely, and remove the push rods.

NOTE: Once broken-in, the rocker arm should be

kept with its corresponding valve.

NOTE: The intake and exhaust push rods are iden-

tical and interchangeable. It is preferable, but not absolutely necessary to return the same push rods to their original locations on engine with substantial (> ing time.

11. Remove the cylinder head bolts using a 14mm wrench. See Figure 9.4.

100 hours) operat-

12. Lift the cylinder head off of the engine.

13. Carefully clean all sealing surfaces of all gasket residue. Do not scratch the sealing surfaces.

NOTE: Make a visual inspection of the valves and

cylinder bore to confirm the initial diagnosis.

To install the cylinder head:

14. Place a new head gasket on the cylinder, allowing the alignment dowels to hold it in place.

Cylinder head

Figure 9.6

Exhaust

port

15. Position the cylinder head on the engine block.

16. Install the 4 head bolts, and tighten them to a step torque of 21 - 22 ft lbs (28 - 30 Nm) in an alternating diagonal pattern. See Figure 9.6.

NOTE: The bolt closest to the exhaust valve must be the

last bolt tightened. Failure to do so will result in the head bolt loosening up.

17. Insert the push rods.

18. Install the rocker arms. Adjust the valve lash by following the steps described in Chapter 1: Intr oductio n.

19. Install the carburetor and air cleaner, using new gaskets, by following the steps described in Chapter 3: Air Intake System.

20. Install the muffler by following the steps described in Chapter 8: Exhaust.

21. Test run the mower in a safe area before returning it to service. Check all safety features.

T65 Series Vertical Shaft Engines

Figure 9.7

Figure 9.8

Valves

Valves and valve parts, like springs and keepers, are not available as service parts. The valves and valve seats can be serviced by grinding and lapping or the hea d can be replace d. Depending on local m achine and labor cost s, it is probably more economical to replace the cylinder head versus servicing the valves.

To service the valves:

NOTE: Warranty valve repairs are to be accom-

plished by replacing the cylinder head.

1. Remove the cylinder head by following the steps

described in the Cylinder Head section of this chapter.

2. Remove the valve retainers by applying light finger

pressure on the valve retainers and sliding them forward. See Figure 9.7.

3. Lift the springs off of the valve stems.

4. Slide the valves out of the cylinder head.

NOTE: Only the intake valve has a va lve guide seal.

See Figure 9.8.

NOTE: Inspect the valves for signs of damage. If a

valve is damaged, replace the cylinder head.

Cylinder head

Figure 9.9

Seat angle is 45

0.043” - 0.050”

Figure 9.10

Inspect for a

burnt edge

5. Inspect the valve seat. See Figure 9.9.

• Valve seats are 45 degrees, with a 15 degree topping cut and a 75 degree narrowing cut.

• Seat width should be 0.043” - 0.050” (1.1 - 1 .3 mm) with a margin of 0.024” (0.6mm) on the exhaust valve and 0.027” (0.7 mm) on the intake valve.

NOTE: The valve seat can be ground to clean it up as long

as the finished seat is within the tolerances listed above. However is may be more economical to replace the head if there is wear or damage to the valve seat.

6. Inspect the valve stem. See Figure 9.10.

7. Inspect the valve springs. NOTE: Valve spring free length should be at least 1.22”

(28.5mm). Original length is 1.44” (36.6 mm).

8. Install the valves in the cylinder head by following steps 2 - 5 in reverse order.

9. Test the valves for leaks by: 9a. Place the cylinder head on a couple of wood

blocks with the valves facing up.

9b. Pour a small amount of gasoline or parts clean-

ing solvent into the combustion chamber (just

enough to cover the valves). 9c. Let the cylinder head sit for ten minutes. 9d. Check for gasoline leaking out of the intake a nd

exhaust ports.

10. Install the cylinder head by following the steps described earlier in this chapter.

1 1. Set the valve lash by following the steps described in

Chapter 1: Introduction.

12. Test run the engine in a safe area before returning it to service.

T65 Series Vertical Shaft Engines

Crankshaft, piston and connecting rod

Figure 10.1

Sump

crankshaft

CHAPTER 10: CRANKSHAFT, PISTON AND CONNECTING ROD

There are a a few different paths that can be followed when disassembling an engine. This chapter will cover the removal of components in one order, but it is written so that the technician can jump around to the component being removed.

The first step to disassemble the engine is to remove the engine from the application by following the steps described in the service manual for that particular application.

1. Drain and save the oil from the engine by following the steps described in Chapter 1: Introduction.

2. Remove the fuel tank by following the steps described in Chapter 4: Fuel system and Governor.

3. Remove the starter by following the steps described in Chapter 6: Starter systems.

4. Remove the flywheel and Ignition Module by following the steps described in Chapter 7: Ignition System.

5. Remove the muffler by following the steps described in Chapter 8: Exhaust.

NOTE: At this point it would be a good idea to service the PCV valve by following the step s described in Chap-

ter 5: Lubrication.

6. Remove the cylinder head by following the steps described in Chapter 9: Cylinder Head.

7. Clean the cylinder bore and remove all carbon.

8. Turn the engine over.

9. Remove the sump bolts using a 10mm wrench.

10. Carefully slide the sump off of the crankshaft. See Figure 10.1.

T65 Series Vertical Shaft Engines

Cam shaft

Compression relief

Figure 10.2

Timing marks

Figure 10.3

Valve tappets

Figure 10.4

Alignment marks

NOTE: The thrust washer should be removed when

the sump is removed.

11. Remove the camshaft. See Figure 10.2. NOTE: Align the timing marks to allow easier

removal of the cam shaft and to help protect the compression relief from damage.

12. Remove the valve tappets. See Figure 10.3.

13. If it is not already done, place alignment marks the connecting rod cap and the connecting ro d so th at they can be reassembled in the proper orientation. See Figure 10.4.

14. Remove the connecting rod cap using a 7 mm wrench.

Crankshaft, piston and connecting rod

Figure 10.5

Cap

Connecting rod

Figure 10.6

Figure 10.7

Lift up on crankshaft

NOTE: Rotating the crankshaft after the connecting rod

bolts are removed will help to separate the connecting rod from the cap. See Figure 10.5.

15. Push the piston out of the cylinder.

16. Remove the piston rings from the piston using a pair of piston ring pliers. See Figure 10.6.

17. Remove the crankshaft. See Figure 10.7.

T65 Series Vertical Shaft Engines

Figure 10.8

Bearing contact

area

Figure 10.9

Crankpin

Figure 10.10

Timing gear

Crankshaft inspection

1. Inspect the crankshaft journals for galling, scoring, pitting or any other form of damage.

2. Measure the journals at the bearing contact points using a vernier caliper or a micrometer. See Figure

10.8.

3. Inspect the crankpin for galling, scoring, pitting or any other form of damage.

4. Measure the crankpin using a vernier caliper or a micrometer. See Fig ure 10.9.

5. Check the crankshaft for straightness by measuring the run out. The crankshaft run out can be checked by:

5a. Place the crankshaft on a pair of matched V-

blocks or in the engine block with the sump installed.

5b. Place a dial indicator at a smooth point at either

end of the crankshaft.

5c. Slowly turn the crankshaft while watching the

dial indicator.

NOTE: Stop the crankshaft before the dial indicator

hits the keyway.

5d. Compare the reading on the dial indicator to the

specification listed at the end of this chapter.

5e. Repeat the above steps on the other en d of the

crankshaft.

6. Inspect the timing gear for wear or damage.

NOTE: The timing gear can be removed from the

crankshaft and replaced if worn or damaged. See Figure 10.10.

Piston Inspection

Figure 10.11

Feeler gauge

Piston ring

Figure 10.12

Top ring

Middle ring

Top ring

Middle ring

3 piece oil ring

Figure 10.13

Crankshaft, piston and connecting rod

1. Clean the piston and remove all carbon from the rings and ring groves.

2. Insert one ring into the cylinder. Push it down about one inch from the top. See Figure 10.11.

3. Measure the end gap with a feeler gauge and compare to the chart at the end of this chapter. See Figure 10.11.

4. Repeat steps 3 and 4 on the other rings.

NOTE: Piston rings are not available as service parts. If

any of the end gaps are out of spec, the engine must be short blocked.

5. Install rings back onto the piston.

NOTE: To help identify the top surface of the piston rings,

they have letter(s) etched on them. See Figure

10.12.

NOTE: The top ring is symmetrical and the middle ring has

a tapered profile. The larger radius of the middle ring should face the crankshaft. See Figure 10.13.

T65 Series Vertical Shaft Engines

Piston

Figure 10.14

Oil ring

Middle ring

Top ring

Piston ring end gap stagger

Figure 10.15

Feeler gauge

NOTE: The piston ring end gaps need to be stag-

gered 90

6. Measure the distance between the ring and the ring land using a feeler gauge and compare the measurement to the chart at the end of this chapter. See Figure 10.15.

apart. See Figure 10.14.

Connecting rod inspection

Figure 10.16

Measure at

right angles

Crankshaft, piston and connecting rod

1. Inspect the connecting rod for cracks or any signs of damage.

2. Install the rod cap and tighten to a torque of 53 -62 in lbs (6 - 7 Nm)

3. Measure the inside diameter of the connecting rod and compare the measurements to those listed in the chart at the end of this chapter. See Figure 10.16.

NOTE: Take two measurements 90 degrees apart. This

will check the out of roundness of the connecting rod.

NOTE: Connecting rods are not a vailable as service p arts.

If the connecting rod is bad, the engine must be short blocked.

4. Take the crankshaft journal measurement and subtract it from the connecting rod measurement to get the connecting rod to journal running clearance. Compare that number to the one liste d in the chart at the end of this chapter.

T65 Series Vertical Shaft Engines

Figure 10.17

Measure the cylinder bore

Figure 10.18

cylinder bore dial indicator

Figure 10.19

Cylinder inspection

1. Clean and inspect the cylinder, inside and out. NOTE: If there is any sign of damage, especially

cracked cooling fins, short block the engine.

NOTE: Take two measurements of the cylinder bor e

90 degrees apart at the top, botto m a nd middle of the cylinder. See Figure 10.17.

NOTE: The measurements can be made using tele-

scoping gauges, inside micrometers or a cylinder bore dial indicator. See Figure 10.18.

2. Compare the measurements to those that are listed in the chart at the end of the chapter.

3. Inspect the cylinder.

NOTE: The cylinder is ma nufactured using a special

NOTE: The cylinder may have some scratches. As

NOTE: If the cylinder needs to be de-glazed,

machining process. This process does not leave a cross hatch that is normally seen in most engines. As the engine breaks in, the cylinder will develop a smooth, dull finish. See Figure 10.19.

long as the scratches cannot be felt with a finger nail, they are acceptable.

replace the cylinder block.

Bearings

Figure 10.20

Sump Oil Seal

Figure 10.21

Measure the bearing ID

Crankshaft, piston and connecting rod

There are two bearings to inspect; a plain bearing in the sump and a plain bearing in the cylinder block. To inspect the bearings:

1. Remove the sump and cylinder block oil seals using a seal puller. See Figure 10.20.

2. Inspect the bearing surface for galling, scratches, metal transfer or any other signs of damage.

3. Measure the inside diameter of the bearings and compare to the chart at the end of this chapter. See Figure 10.21.

T65 Series Vertical Shaft Engines

Figure 10.22

Tecumseh seal driver

Figure 10.23

Seal protector

Figure 10.24

arrow

push rod cavity

Reassembly

1. Clean the cylinder 1a. Remove all gasket material from all mating

surfaces.

1b. Clean the cylinder and sump.

2. Oil seals 2a. Install a new oil seal in the cylinder block. 2b. Install a new seal in the sump. See Figure

10.22.

NOTE: A Troy-Bilt tiller seal service tool # TWX-

4006, Tecumseh Seal driver 670272 or a piece of 1” schedule 40 PVC pipe can be used to install the sump oil seal.

3. Insert the crankshaft into the cylinder block bearing. NOTE: Pre-lube the crankshaft with clean 10W-30

motor oil or engine assembly lube.

4. Install the crankcase oil seal using a seal protector to protect the oil seal lip. See Figure 10.23.

5. Install the piston by: 5a. Compress the piston rings using a piston ring

compressor.

5b. Pre-lube the cylinder wall with clean 10W-30

motor oil

5c. Slide the connecting rod and piston into the

cylinder.

NOTE: The arrow on the piston must point towards

the push rod cavity. See Figure 10.24.

Cub Cadet T65 Series User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

CHAPTER 1: INTRODUCTION

Professional Service Manual Intent

Safety

Fasteners

Assembly instructions

Model and serial number

Maintenance

Spark plugs

Air filter

Oil type and capacity

Changing the oil

Fuel filter

Fuel system

Servicing the fuel system

Valve lash

Exhaust system

Cleaning the engine

General torque specifications

Definitions

CHAPTER 2: BASIC TROUBLESHOOTING

Introduction

Steps to troubleshooting

Define the problem

Identify factors that could cause the problem

Repairing the problem

Prime test

Leak-down test

Compression test

PCV testing

Troubleshooting flow charts

Air filter

CHAPTER 3: AIR INTAKE SYSTEM

Air Filter Housing

Carburetor Insulator

CHAPTER 4: THE FUEL SYSTEM AND GOVERNOR

Fuel Line

Inspect the fuel lines

Inspecting the fuel

Test fuel for alcohol

The fuel filter

Evaporative (EVAP) emissions system

Charcoal canister fuel caps

Fuel tank vent

The fuel tank

Autochoke

Temperature compensator

Primer

Carburetors

Inspecting the carburetor:

Disassembly and rebuilding the carburetor

Governor

Governor shaft

Governor cup and the governor gear

CHAPTER 5: LUBRICATION

Oil type and quantity

Oil dipstick

Dipstick tube removal

Lubrication system

Recoil Starter Removal

CHAPTER 6: STARTER AND CHARGING SYSTEMS

Starter Rope

Starter pulley and recoil spring

Troubleshooting the ignition system

CHAPTER 7: IGNITION SYSTEM

Troubleshooting the Stop Switch

Troubleshooting the Module

About the spark plug

Cleaning the spark plug

Inspection of the spark plug

Spark plug removal

Ignition Module

Engine brake and stop switch (if equipped)

Flywheel

CHAPTER 8: EXHAUST

Muffler

Cylinder Head