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.

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