Toro 62901, 62902, 58355, 58356, 51620 Service Manual
...
A-31 ENGINE SERVICE MANUAL
Table of Contents – Page 1 of 1
GENERAL INFORMATION
GENERAL SPECIFICAT IO NS
TORQUE SPECIFICATIONS
SAFETY WARNINGS AND NOTES
OPERATION AND MAINTENANCE
TROUBLESHOOTING
ENGINE FAILS TO START
ENGINE STARVES ON ACCELERATION
ENGINE IS HARD TO START
ENGINE STALLS
ENGINE FIRES INTERMITTENTLY
ENGINE DOES NOT PRODUCE MAXIMUM POWER
CARBURETOR FLOODS
ENGINE STOPS AFTER RUNNING BRIEFLY
ENGINE WILL NOT IDLE
ENGINE BACKFIRES OR MISFIRES
ENGINE WILL NOT ACCELERATE
ENGINE LACKS POWER OR STOPS DURING OPERATION
DISASSEMBLY, INSPECTION, & REPAIR
TYPICAL DISASSEMBLY SEQUENCE
DISASSEMBLE MAJOR COMPONENTS
DISASSEMBLE ENG IN E
REASSEMBLY
TYPICAL ASSEMBL Y SEQU E NCE
ENGINE REASSEMBLY
INSTALL MAJOR COMPONENTS
GENERAL INFORMATION
General Information .........................
Troubleshooting ............................
Disassembly, Inspection and Repair .................
Reassembly ..............................
1
2
3
4
1-1
GENERAL INFORMATION
1
General Specifications ...............1-3
Engine ......................1-3
Fuel And Lubrication ...............1-3
Ignition ......................1-3
Torque Specifications ................1-4
Air Filter ......................1-4
Carburetor ....................1-4
Carburetor Mount/Reed Plate ..........1-4
Table Of Contents
Clutch .......................1-4
Crankcase And Cylinder .............1-5
Flex Drive Housing (Boom) ............1-5
Flywheel .....................1-5
Ignition Module ..................1-5
Ignition Switch ..................1-6
Muffler ......................1-6
Starter/Starter Housing ..............1-6
Safety Warnings and Notes .............1-7
Operation and Maintenance .............1-8
Product Identification Numbers ..........1-8
Fuel Recommendations .............1-8
Fuel and Oil Mixing Instructions .........1-9
1-2
Starting/Stopping Instructions ..........1-9
Service/Maintenance Instructions ........1-11
Storage Instructions ...............1-14
Special Tools ...................1-15
General Specifications
GENERAL INFORMATION
Engine
Item
Engine Type Air-cooled, 2-Cycle
Displacement 1.9 cu. in. (31 cc)
Bore 1.37 in. (34.80 mm)
Stroke 1.25 in. (31.75 mm)
Average Compression 90-120 lbs. (41-55 kg)
Piston Ring Width 0.046 in. (1.16 mm)
Piston Ring End Gap 0.085 in. (2.159 mm)
Piston Ring Side Clearance 0.005 in. max (0.127 mm)
1
Fuel And Lubrication
Item
Lubrication Fuel/Oil Mixture
Fuel/Oil Ratio 32:1
Approx. Fuel Tank Capacity 18 oz (530 ml)
Ignition
Item
Ignition Type C.D. Electronic Ignition
Ignition Module Air Gap 0.010-0.015 in. (0.254-0.381 mm)
Spark Plug Type Champion® DJ8J
Spark Plug Gap 0.025 in (0.635 mm)
1-3
GENERAL INFORMATION
Torque Specifications
Air Filter
1
Item
Air Filter Cover Mounting Screws 15-25 in•lb (1.7-2.8 N•m)
Carburetor
Item
Carburetor/Choke Plate Mounting Screws 35-40 in•lb (3.9-4.5 N•m)
Throttle Wire Swivel Screw 9-12 in•lb (1.0-1.4 N•m)
Carburetor Mount/Reed Plate
Item
Carburetor Mount/Reed Plate Mounting Screws 60-65 in•lb (6.8-7.3 N•m)
Reed Valve/Reed Backup Plate Mounting Screw(s) 15-20 in•lb (1.7-2.3 N•m)
Clutch
Item
Clutch Cover Mounting Screws 35-40 in•lb (3.9-4.5 N•m)
Clutch Drum Screw 38-44 in•lb (4.3-5.0 N•m)
Clutch Rotor 150-160 in•lb (16.9-18 N•m)
1-4
GENERAL INFORMATION
Crankcase And Cylinder
Item
Crankcase (Cylinder) Mounting Screws 110-120 in•lb (12.4-13.5 N•m)
Crankcase Cover Mounting Screws 67 in•lb (7.5 N•m)
Fan Shroud Mounting Screws 110-120 in•lb (12.4-13.5 N•m)
Spark Plug 190-210 in•lb (21.4-23.6 N•m)
Flex Drive Housing (Boom)
Item
1
Boom Clamp Nut 70-80 in•lb (7.9-9.0 N•m)
Anti-rotation Screw 15-20 in•lb (1.7-2.3 N•m)
Flywheel
Item
Flywheel Mounting/Square Drive Nut (Non-clutch Models) 150-160 in•lb (16.9-18 N•m)
Flywheel Mounting/Crankshaft Extension Nut (Blowers) 150-160 in•lb (16.9-18 N•m)
Ignition Module
Item
Ignition Module Mounting Screws 28-35 in•lb (3.2-3.9 N•m)
1-5
GENERAL INFORMATION
Ignition Switch
Item
1
Slide Switch Contact To Switch Cover Screw 7-12 in•lb (0.8-1.4 N•m)
Slide Switch Contact To Starter Housing Screw 10-15 in•lb (1.1-1.7 N•m)
Stop Switch Lead To Starter Housing Screw 10-15 in•lb (1.1-1.7 N•m)
Toggle Switch Nut 25-35 in•lb (2.8-3.9 N•m)
Muffler
Item
Muffler Exhaust Tube Screws 15-25 in•lb (1.7-2.8 N•m)
Muffler Heat Shield Screw 15-25 in•lb (1.7-2.8 N•m)
Muffler Mounting Screws
Serial Numbers Prior to 809000000 56 in•lb (6.3 N•m)
Serial Number 809000000 and Greater 80-90 in•lb (9.0-10.1 N•m)
Starter/Starter Housing
Item
Shroud Extension/Engine Stand Screw 25-35 in•lb (2.8-3.9 N•m)
Starter Housing Screws 35-40 in•lb (4.1-4.5 N•m)
Starter Pulley Retainer Screw(s) 20-30 in•lb (2.3-3.4 N•m)
Handle Bracket Screws (Cultivators) 35-40 in•lb (4.1-4.5 N•m)
1-6
GENERAL INFORMATION
SAFETY WARNINGS AND NOTES
The purpose of safety symbols is to attract your
attention to possible dangers. The safety symbols and
the explanations with them, deserve your careful
attention and understanding. The safety warnings do
not by themselves eliminate any danger. The
instructions or warnings they give are not substitutes
for proper accident prevention measures.
WARNING: For Your Safety!
Highlights instructions which failure to obey can result
in personal injury.
NOTE: Advises of information which maybe useful while performing maintenance or repair of the
equipment. Also highlights instructions which failure to obey can result in damage to parts or equipment.
WARNING: Spring Under Tension!
WARNING: Explosive Fuel!
Gasoline may be present in the fuel tank, carburetor,
fuel lines, or crankcase. Gasoline is extremely flammable and its vapors can explode if ignited. Keep
sparks, flames, and other sources of ignition away
from the engine. Do not smoke while servicing the
engine. Never use gasoline as a cleaning agent.
Store gasoline only in approved containers, in wellventilated, unoccupied buildings, away from sparks,
flames, or other sources of ignition. Do not fill the fuel
tank while the engine is hot or running, since spilled
fuel could ignite if it comes in contact with hot parts or
sparks from ignition. Do not start the engine near
spilled fuel. Do not smoke while handling gasoline or
filling the fuel tank.
WARNING: Cracked or Broken Cooling Fins
Are A Hazard!
Be careful not to crack or break any cooling fins. They
could fly off during operation. If cooling fins are
cracked or broken, replace the flywheel.
1
The rope starter on these engines contains a flat wire
spring that is under tension. Wear eye and hand
protection when replacing worn or broken spring, in
case it should uncoil as it is handled. Allow spring
tension to be completely relieved and make sure
pulley disengages from spring before removing the
pulley retainer(s), pulley, andstarter spring from
housing.
WARNING: Electrical Shock!
Never touch electrical wires or components while the
engine is running. They can be sources of electrical
shock.
WARNING: Hot Surfaces!
The muffler, cylinder, crankcase, trimmer cutting head,
and other engine surfaces get extremely hot from
operation. These surfaces remain hot for a short
period of time after the engine is stopped. To prevent
severe burns, allow the engine to cool completely
before servicing.
1-7
GENERAL INFORMATION
OPERATION AND MAINTENANCE
1
PRODUCT IDENTIFICATION
NUMBERS
When ordering parts, or in any communication involving an engine or product, always give the:
• Model Number, and
• Serial Number
These numbers are located on a decal (or decals) affixed to the unit (Figure 1-1). The identification decal(s) will be located on the engine, metal boom, or
plastic housing. The actual location will vary depending on the type of product.
Fuel Recommendations
WARNING: Explosive Fuel!
Gasoline is extremely flammable and its vapors can
explode if ignited. Store gasoline only in approved
containers, in well-ventilated, unoccupied buildings,
away from sparks or flames. Do not fill the fuel tank
while the engine is hot or running, since spilled fuel
could ignite if it comes in contact with hot parts or
sparks from ignition. Do not start the engine near
spilled fuel. Do not smoke while handling gasoline.
Never use gasoline as a cleaning agent.
NOTE: READ THESE INSTRUCTIONS CAREFULLY BEFORE ATTEMPTING TO START OR
OPERATE THIS UNIT. Using old oil or fuel, or improperly mixing the oil and fuel can cause engine
damage. This type of damage will void the engine
warranty.
Recommended Oil Type
Figure 1-1A. Product Identification Plate.
Toro 2-cycle oil is recommended for use in these engines (Figure 1-2). If another brand of 2-cycle oil is
used, use a high quality oil that is formulated for small
2-cycle air-cooled engines.
2.6078.001
Figure1-2. Recommended Oil Type.
Recommended Fuel Type
Use clean, fresh, regular grade unleaded gasoline.
Figure 1-1B. Product Identification Plate.
1-8
1.0762.005
NOTE: Alcohol blended fuel absorbs moisture
(water). As little as 1% moisture in the fuel can cause
fuel and oil to separate and form acids when stored.
GENERAL INFORMATION
If these types of fuel must be used, use fresh fuel (less
than 60 days old) and mix according to the instructions
in this section.
Use Of Blended Fuels
If you choose to use a blended fuel or its use is
unavoidable, the following precautions are
recommended.
1. Always use fresh fuel mixed according to the
instructions in this section.
2. Use the special additive Alcohol Protector®
(by Gold Eagle) or equivalent to inhibit corrosion
and reduce oil/fuel separation (mix as directed).
3. Always agitate the fuel mix before fueling unit.
4. Drain the fuel tank and run engine dry before
storing unit.
oz. (11 ml) per gallon of gasoline or mix per instructions on container. NEVER add fuel additives directly
to the unit fuel tank.
Fuel And Oil Mixing Instructions
NOTE: For proper engine operation and maximum re-
liability, pay strict attention to these fuel and oil mixing
instructions. Use a 32:1 fuel/oil ratio when using Toro
2-cycle oil. Using improperly mixed fuel can severely
damage the engine. Never mix the gasoline and oil in
the fuel tank of the unit.
Use the following procedures to ensure complete mixing:
1. Put a small amount of fresh gasoline into a clean 1
U.S. gallon (3.785 liter) fuel can.
2. Add 4-oz. (118 ml) of Toro 2-cycle engine oil.
3. Fill the remainder of the fuel can with gasoline.
1
Problems With Blended Fuels
Some problems associated with blended fuels include:
• Vapor lock
• Poor warm restart
• Poor performance at high altitudes
• Corrosion of fuel system components
If any of these symptoms occur, switch to regular, unleaded gasoline.
Gasohol Use May Require Carburetor Adjustments
These engines are lubricated by oil mixed with fuel.
Using blended fuel may alter the air/fuel ratio causing
a lean mix (less fuel, more air).
If this condition is not corrected by adjusting the carburetor, engine damage due to poor lubrication can result.
Use Of Fuel Additives
4. Screw the fuel can cap on tightly and SHAKE THE
CAN VIGOROUSLY FOR 30 SECONDS.
Starting/Stopping Instructions
To Start The Engine
1. If the unit is equipped with an ignition switch, make
sure the switch is in the “START” or “ON” position
(Figure 1-3).
The use of fuel additives such as Toro Gas Conditioner/Stabilizer or an equivalent, will minimize the formation of fuel gum deposits. Such an additive should
only be used when fuel/oil mix is prepared. Add 0.4
1-9
GENERAL INFORMATION
1
Slide
Switch
Toggle
Switch
Figure 1-3. Typical Ignition Switches.
2. If the unit is equipped with a primer bulb, FULLY
PRESS AND RELEASE the primer bulb 5 to 7
times (Figure 1-4).
Figure 1-4. Primer Bulb.
2.6078.003
2.6078.004
Figure 1-5. Typical Choke Controls.
4. Place the unit in the starting position (with the trimmer cutting head, cultivator tines, or blower nozzle
away from yourself and others).
5. Squeeze the throttle trigger to “FULL THROTTLE”
(Figure 1-6). Hold or lock the throttle in this position.
3.6078.005
3. Place the choke knob or choke lever in the FULL
“CHOKE” position (Figure 1-5).
1-10
Figure 1-6. Typical Throttle Control.
6. Pull the starter rope BRISKLY until you hear the engine sound like it wants to run (normally 2 to 5
pulls).
7. Place the choke knob or choke lever in the “PARTIAL” choke position (Figure 1-5).
8. Pull the starter rope BRISKLY 1 to 3 pulls to start
the engine.
3.6078.006
9. If the engine does not start, repeat steps 1 to 8.
GENERAL INFORMATION
10. After the engine warms up for 5 to 10 seconds,
place the choke knob or choke lever in the “RUN”
position.
To Stop The Engine
Place the ignition switch in the “OFF” or “STOP” position. For those units with a momentary (or push-tostop) type switch, push and hold the button or lever
until the engine stops completely (Figure 1-7).
Figure 1-8. Washing Air Filter Element.
3. Apply clean SAE 30 oil to the air filter (Figure 1-9).
3.6078.008
1
Figure 1-7. Typical Stop Button.
Service/Maintenance Instructions
Air Filter
NOTE: CLEAN AND RE-OIL THE AIR FILTER
EVERY 10 HOURS OF OPERATION. The air filter is
one of the most important areas to maintain. If it is not
maintained as follows, severe engine damage can
result.
1. Remove the air filter from the carburetor/air filter
cover assembly. Refer to Part 3 - Engine Disassembly.
2. Wash the air filter in detergent and water (Figure 1-
8). Rinse the air filter thoroughly in clean water
and allow it to dry.
2.6078.007
Figure 1-9. Oiling Air Filter Element.
4. Squeeze the air filter to ensure that the oil is spread
throughout the entire filter (Figure 1-10).
3.6078.009
1-11
GENERAL INFORMATION
1
4. Check the spark plug gap using a wire feeler gauge.
Set the gap to 0.025 inch (0.635 mm) (Figure 1-
11).
5. Reinstall the spark plug and torque to 190-210 in•lb
(21.4-23.6 N•m).
Figure 1-10. Squeezing Excess Oil From Air
Filter Element.
5. Reinstall the air filter in the carburetor/air filter
cover assembly. Refer to Part 4 - Engine Assembly.
Spark Plug
Every 50 hours of operation, remove the spark plug,
check its condition, and reset the gap or replace with a
new plug as necessary.
WARNING: Electrical Shock!
Never touch electrical wires or components while the
engine is running. They can be sources of electrical
shock.
1. Before removing the spark plug, clean the area
around the base of the spark plug to keep dirt and
debris out of the engine.
2. Disconnect the spark plug wire and remove the
spark plug from engine.
3.6078.010
Figure 1-11. Spark Plug Gap.
Carburetor Adjustment
These engines are equipped with a diaphragm-type
carburetor. The carburetor has been carefully calibrated at the factory. In most cases, no further adjustment will be required.
The condition of the air filter is very important to the operation of the trimmer. A dirty air filter will restrict the
air flow to the carburetor. This in turn upsets the fuelair mixture in the carburetor. The resulting symptoms
are often mistaken for an out-of-adjustment carburetor.
Therefore, check the condition of the air filter before
adjusting the carburetor. Refer to “Air Filter” Service/Maintenance Instructions.
If the following conditions are experienced, it may be
necessary to adjust the carburetor.
2.6081.011
3. Inspect the spark plug for carbon buildup and clean
if necessary. Replace the plug if it is badly burnt or
if reuse is questionable.
NOTE: Do not clean the spark plug in a machine
which uses abrasive grit. Some grit could remain
on the spark plug and enter the engine causing
extensive damage.
1-12
• The engine will not idle.
• The engine hesitates or stalls on acceleration.
• The loss of engine power, which is not corrected
by cleaning the air filter.
• The engine operates in an erratic or fuel-rich
condition (indicated by excessive exhaust smoke
from the muffler).
GENERAL INFORMATION
NOTE: Follow these carburetor adjustment proce-
dures carefully. An incorrectly adjusted carburetor can
cause severe engine damage.
Make sure the unit is fully assembled before making
carburetor adjustments:
For trimmers and brush cutters, make sure the boom,
cutting head, and line guard are installed and the cutting line is extended to its full cutting length.
For cultivators, make sure the boom and gear box are
installed.
For blowers and blower-vacs, make sure the blower
tube and nozzle are installed.
The carburetor has three basic adjustments: the idle
speed adjustment, the idle mixture adjustment, and
the high speed mixture adjustment (Figure 1-12).
(H) High Speed
Mixture Needle
(L) Idle
Mixture Needle
needles clockwise until they are lightly seated.
Then turn the needles counterclockwise the following number of turns:
1
High Speed Mixture Needle:1-1/4 turns
Idle Mixture Needle: 1-1/4 turns
NOTE: Turn the high speed mixture and idle mixture needles finger-tight. Do not force the needles
with a screwdriver as this can damage the tips of
the needles and the seats in the carburetor body.
5. Start engine and allow it to warm up for 3 to 5 minutes.
NOTE: For the following steps, use a magnetic
pick-up 2-cycle engine tachometer to monitor engine speed.
Idle Speed
Figure 1-12. Carburetor Adjustments.
3.6081.012
1. Remove air filter cover assembly as instructed in
Part 3 — Engine Disassembly.
2. Initial Idle Speed Setting: Turn idle speed screw
counterclockwise until it does not touch the throttle
lever. Now turn the screw clockwise until it just
touches the throttle lever; then continue turning 2
full turns.
3. If so equipped, remove the rubber cap from the high
speed mixture adjustment needle.
4. Initial High Speed Mixture and Idle Mixture Settings:
Turn both the high speed mixture and idle mixture
6. Final High Speed Mixture Setting: Squeeze the throttle trigger to the FULL (WIDE OPEN) THROTTLE
position. Turn the high speed mixture needle clockwise or counterclockwise to set the high speed
RPM:
Trimmers and Cultivators: 6,800 to 7,200 RPM
Blowers and Blower-Vacs: 6,600 to 7,200 RPM
7. Release the throttle trigger and let the engine idle. If
the engine stops, turn the idle speed screw clockwise 1/8 turn at a time until the engine idles.
8. Final Idle Mixture and Idle Speed Settings: Adjust
the the idle mixture and idle speed as follows:
a. Turn the idle mixture needle clockwise until the
fastest idle RPM is reached; then turn the needle counterclockwise 1/8 turn.
b. Squeeze the throttle trigger. If the engine falters
or hesitates as it accelerates, turn the idle mixture needle counterclockwise 1/16 turn at a
time until the engine accelerates rapidly.
1-13
GENERAL INFORMATION
c. If the idle speed has changed significantly be-
cause of steps a. and b. above, readjust the
idle speed screw.
1
The recommended idle speed for all products
is 3,000 to 3,200 RPM.
9. Stop the engine. Install the air filter and restart the
engine. Recheck the operation and readjust as
necessary.
10. Make sure the air filter cover is reinstalled securely
before placing the unit back into service.
Governed Carburetor Check
Some units are equipped with fuel-governed carburetors. If so equipped, and after adjusting the carburetor,
check the operation of the governor on trimmers and
brush cutters as follows:
1. Clip or wind the cutting line so it is inside the
cutting head (not extended to its full cutting length).
Do not smoke while handling gasoline. Never use
gasoline as a cleaning agent.
Storage For 45 To 60 Days
Use the following storage procedure for equipment or
fuel that will be stored for more than 45 days and less
than 60 days:
Equipment - Empty the fuel tank and run the unit until
the fuel system is empty. When starting the unit after
storage, refill the fuel tank with freshly mixed gasoline
and oil.
Fuel - Do not use fuel that has been stored for more
than 60 days. Dispose of the old fuel in a safe manner
and use a fresh mix.
Storage For More Than 60 days
1. Drain all fuel from the fuel tank into an approved
fuel container.
2. Start the engine and run it until it stalls.
2. Start the engine and run it at FULL (WIDE OPEN)
THROTTLE.
The maximum high speed RPM should not exceed 8,800 RPM.
3. If the high speed RPM exceeds 8,800 RPM, the
governor assembly in the carburetor must be
cleaned or replaced and the carburetor readjusted.
Storage Instructions
WARNING: Explosive Fuel!
Gasoline is extremely flammable and its vapors can
explode if ignited. Store gasoline only in approved containers, in well-ventilated, unoccupied buildings, away
from sparks or flames. Do not fill the fuel tank while
the engine is hot or running, since spilled fuel could ignite if it comes in contact with hot parts or sparks from
ignition. Do not start the engine near spilled fuel.
3. Allow the engine to cool. Remove the spark plug
and put about 1 oz. (39 ml) of any high quality motor or 2-cycle oil into the cylinder. Pull the starter
rope slowly to distribute the oil. Reinstall the spark
plug.
4. Clean the unit and inspect for any loose or
damaged parts. Repair or replace damaged parts
and tighten loose screws, nuts, or bolts.
5. Store the unit in a dry, well ventilated area.
To Reactivate Unit For Service
1. Remove the spark plug and drain the oil from the
cylinder by slowly pulling the starter rope.
2. Reinstall the spark plug.
3. Refuel the unit with a fresh gasoline /oil mixture.
Start engine in accordance with the Starting Instructions.
1-14
Special Tools
GENERAL INFORMATION
In addition to typical hand tools, the following special
tools are required to properly service these engines:
• Clutch Tool, P/N 147337 (Figure 1- 13) or P/N
180918 (Figure 1-14).
• Flywheel Holder, P/N 612470(Figure 1-15) or P/N
180919(Figure 1-16).
• Flywheel Strap Wrench or Spanner Wrench
(Commercially available).
• 0-250 in•lb (0-28.1 N•m) Torque Wrench
(Commercially available).
• Torx® Screwdriver or Bit Set (Commercially
available).
• Two-stroke, Magnetic Pick-up Tachometer
(Commercially available).
• Arbor or Hydraulic Press (Commercially
available).
• Bearing And Seal Pullers (Commercially
available).
Figure 1-14.Clutch Tool, P/N 180918.
1
3.6051.022
Figure 1-13. Clutch Tool, P/N 147337.
3.6069.011
Figure 1-15 Flywheel Holder, P/N 612470.
Figure 1-16 Flywheel Holder, P/N 180919.
3.6069.013
3.6051.023
1-15
GENERAL INFORMATION
1
1-16
TROUBLESHOOTING
General Information ..........................
Troubleshooting ...........................
Disassembly, Inspection and Repair .................
Reassembly ..............................
1
2
3
4
2-1
TROUBLESHOOTING
Engine Fails To Start ................2-3
Engine Starves On Acceleration ..........2-4
Engine Is Hard To Start ...............2-4
2
Engine Stalls .....................2-5
Engine Fires Intermittently ..............2-5
Engine Does Not Produce Maximum Power ....2-6
Table Of Contents
Carburetor Floods ..................2-6
Engine Stops After Running Briefly .........2-7
Engine Will Not Idle .................2-7
Engine Backfires Or Misfires ............2-7
Engine Will Not Accelerate .............2-8
Engine Lacks Power Or Stops During Operation . . 2-8
2-2
TROUBLESHOOTING
When difficulties occur, be sure to check for simple
causes which, at first, may seem too obvious to be
considered. A starting problem, for example, could be
caused by an empty fuel tank.
The following table lists some common causes of
operating troubles and the possible causes and
remedies.
Engine Fails To Start
Possible Cause Remedy
Ignition switch OFF Turn switch ON
Out of fuel or water in fuel Drain tank and blow out fuel lines to remove
water. Refuel tank with fresh fuel mixture.
Dirty or plugged air filter Clean or replace air filter
Loose spark plug lead wire Reconnect lead wire
Fouled, improperly gapped, or broken spark plug Clean or replace spark plug; set gap to
0.025 inch (0.635 mm)
2
Plugged fuel tank cap vent Clean fuel tank cap vent
Plugged or waterlogged fuel filter Replace fuel filter
Improperly adjusted carburetor Adjust carburetor
Plugged muffler Clean or replace muffler
Faulty primer or primer/fuel lines improperly installed Correctly install primer/fuel lines or replace
primer
Incorrect fuel mixture Drain tank; refill with correct fuel mixture
Plugged fuel line Blow out fuel line
Faulty carburetor diaphragm Replace diaphragm
Plugged fuel pump filter screen Clean or replace filter screen
Faulty fuel pump diaphragm Replace pump diaphragm
Plugged carburetor/fuel pump passages Clean out passages
Incorrect air gap between flywheel and Ignition module Set ignition module air gap to
0.010-0.015 in. (0.254-0.381 mm)
Faulty ignition module Replace ignition module
Faulty reed valve Replace reed valve
Low compression Replace piston ring or gasket
2-3
TROUBLESHOOTING
Engine Starves On Acceleration
Possible Cause Remedy
Plugged fuel filter Replace fuel filter
Improperly adjusted carburetor Adjust carburetor about 1/8 turn
2
Engine Is Hard To Start
Possible Cause Remedy
Fouled, improperly gapped, or broken spark plug Clean or replace spark plug; set gap to
0.025 inch (0.635 mm)
Plugged or waterlogged fuel filter Replace fuel filter
Improperly adjusted carburetor Adjust carburetor
Clogged muffler Clean or replace muffler
Faulty primer or primer/fuel lines improperly installed Correctly install primer/fuel lines or
replace primer
Incorrect air gap between flywheel and ignition module Set ignition module air gap to
0.010-0.015 in. (0.254-0.381 mm)
Faulty ignition module Replace ignition module
Worn or improperly adjusted carburetor jet needle Adjust or replace needle
Faulty carburetor diaphragm Replace carburetor diaphragm
Faulty fuel pump diaphragm Replace fuel pump diaphragm
Faulty reed valve Replace reed valve
Low compression Replace piston ring or cylinder gasket
2-4
TROUBLESHOOTING
Engine Stalls
Possible Cause Remedy
Dirty or plugged air filter Clean or replace air filter
Fouled, improperly gapped, or broken spark plug Clean or replace spark plug; set gap to
0.025 inch (0.635 mm)
Plugged fuel tank cap vent Clean fuel tank cap vent
Incorrect fuel mixture Drain tank; refill with correct fuel mixture
Improperly adjusted carburetor Adjust carburetor
Plugged muffler Clean or replace muffler
Plugged fuel line Blow out fuel line
Faulty ignition module Replace ignition module
Engine Fires Intermittently
Possible Cause Remedy
Fouled, improperly gapped, or broken spark plug Clean or replace spark plug; set gap to
0.025 inch (0.635 mm)
Incorrect air gap between flywheel and ignition module Set ignition module air gap to
0.010-0.015 in. (0.254-0.381 mm)
Faulty ignition module Replace ignition module
2
Incorrect fuel mixture Drain tank; refill with correct fuel mixture
2-5
TROUBLESHOOTING
Engine Does Not Produce Maximum Power
Possible Cause Remedy
Plugged air filter Clean or replace air filter
Incorrect fuel mixture Drain tank; refill with correct fuel mixture
Plugged muffler Clean or replace muffler
Plugged or waterlogged fuel filter Replace fuel filter
2
Improperly adjusted carburetor Adjust carburetor
Leaking reed valve Replace reed valve
Air leak at carburetor base gasket Tighten carburetor fasteners or
replace carburetor base gasket
Intermittent spark Replace ignition module
Low compression Replace piston ring or cylinder gasket
Leaking crankcase seals Replace crankcase seals
Scored piston and/or cylinder Replace piston and cylinder assembly
Worn piston ring or low compression Overhaul engine
Carburetor Floods
Possible Cause Remedy
Faulty primer or improperly installed primer/fuel lines Correctly install primer/fuel lines
or replace primer
Improperly adjusted carburetor Adjust carburetor
Damaged carburetor Replace carburetor
Leaking fuel inlet needle Replace fuel inlet needle
2-6
TROUBLESHOOTING
Engine Stops After Running Briefly
Possible Cause Remedy
Partially plugged fuel tank cap vent Clean fuel tank cap vent
Dirty or plugged air filter Clean or replace air filter
Water in fuel mixture Drain tank and blow out lines
Air leak at carburetor base gasket Tighten carburetor mounting fasteners
or replace carburetor base gaskets
Dirty carburetor fuel inlet needle or passage Replace fuel inlet needle
or clean out carburetor
Faulty carburetor diaphragm Replace diaphragm
Losing compression Replace piston ring or gaskets,
or overhaul engine
2
Engine Will Not Idle
Possible Cause Remedy
Improperly adjusted carburetor Adjust carburetor
Faulty carburetor diaphragm Replace carburetor diaphragm
Faulty carburetor inlet seat gasket Replace carburetor inlet seat gasket
Leaking crankshaft seals Replace crankshaft seals
Leaking or broken reed valve Replace reed valve
Scored cylinder or low compression Overhaul engine
Engine Backfires Or Misfires
Possible Cause Remedy
Improper or contaminated fuel mix Drain tank; refill with fresh fuel mixture
Fouled, improperly gapped, or broken spark plug Clean or replace spark plug; set gap to
0.025 inch (0.635 mm)
Faulty reed valve Replace reed valve
Shorted ignition module leads Check for loose or bare wires or loose
assembly and correct,or
replace or replace ignition module
2-7
TROUBLESHOOTING
Engine Will Not Accelerate
Possible Cause Remedy
Carburetor improperly adjusted Adjust carburetor
Air filter clogged Clean or replace air filter
Spark plug fouled Clean spark plug and set gap to
0.025 inch (0.635 mm) or replace plug
Plugged muffler Clean or replace muffler
2
Carburetor diaphragm gasket leaking Replace gasket
Reed leaking or broken Replace reed
Engine Lacks Power Or Stops During Operation
Possible Cause Remedy
Faulty primer causing flooding Replace primer
Dirty or plugged air filter Clean or replace air filter
Plugged muffler Clean or replace muffler
Scored cylinder or low compression (below 90 psi) Overhaul engine
2-8
DISASSEMBLY, INSPECTION, & REPAIR
General Information ..........................
Troubleshooting ............................
Disassembly, Inspection and Repair ................
Reassembly ..............................
1
2
3
4
3-1
DISASSEMBLY, INSPECTION, & REPAIR
Table Of Contents
Typical Disassembly Sequence ...........3-5
Disassemble Major Components ..........3-6
Drain Fuel From Tank ..............3-6
Remove Engine .................3-6
Trimmers ...................3-6
Cultivators ...................3-7
Blowers And Blower/Vacs ...........3-8
3
Remove Styling Cover ..............3-8
Remove Air Filter .................3-9
Round Air Filter—Trimmers And
Cultivators ...................3-9
Square Air Filter—Trimmers And
Cultivators ...................3-10
Square Air Filter—Blowers And
Blower/Vacs ..................3-10
Remove Choke/Carburetor ............3-11
Round Air Filter—Trimmers And
Cultivators ...................3-11
Square Air Filter—Trimmers And
Cultivators ...................3-12
Square Air Filter—Blowers And
Blower/Vacs ..................3-14
3-2
Remove Primer Bulb .............3-15
Carburetor Disassembly, Inspection,
Repair, And Reassembly .............3-16
Carburetor Disassembly ...........3-16
Fuel Metering Side ..............3-16
Fuel Pump Side ................3-17
Inspection and Cleaning ...........3-18
DISASSEMBLY, INSPECTION, & REPAIR
Carburetor Reassembly ............3-19
Fuel Metering Side ..............3-19
Fuel Pump Side ................3-21
Final Carburetor Adjustment .........3-22
Remove Carburetor Mount/Reed
Plate And Fuel Tank ...............3-22
Trimmers And Cultivators ...........3-22
Blowers And Blower/Vacs ...........3-22
Fuel Tank And Lines Disassembly,
Inspection, And Reassembly ...........3-23
Fuel Tank And Cap ..............3-23
Fuel Line And Filter Removal .........3-23
3
Fuel Line And Filter Installation ........3-24
Reed And Reed Backup Plate
Removal And Installation ............3-24
Reed And Reed Backup Installation .....3-25
Remove Muffler .................3-26
Heat Shield Removal .............3-27
Exhaust Exit Tube Removal .........3-27
Inspection And Cleaning ...........3-28
Muffler Reassembly ..............3-28
Remove Clutch ..................3-29
Inspection ...................3-30
Remove Starter Housing .............3-31
Trimmers And Cultivators ...........3-31
Blowers And Blower/Vacs—
Models 280, 300BV, 310, And 310BV ....3-32
Ignition Switch Replacement .........3-33
Toggle Switch ...............3-33
Slide Switch ................3-33
Push Button Switch ............3-34
3-3
DISASSEMBLY, INSPECTION, & REPAIR
Starter Disassembly, Repair,
And Reassembly .................3-34
Adding Starter Spring Tension ........3-34
Starter Disassembly ..............3-35
Inspection And Service ............3-37
Starter Reassembly ..............3-37
Remove Ignition Module .............3-40
Remove Flywheel ................3-40
Flywheel Inspection And Repair .......3-41
3
Remove Fan Shroud ...............3-42
Remove Spark Plug, Cylinder,
And Piston/connecting Rod Assembly ......3-42
Cylinder And Piston Inspection ........3-44
Remove Crankshaft, And Crankcase
Disassembly, Inspection, And Reassembly . . . 3-44
Crankcase Disassembly ...........3-44
Inspection ...................3-46
Crankcase Reassembly ............3-46
3-4
DISASSEMBLY, INSPECTION, & REPAIR
Typical Disassembly Sequence
The following sequence is suggested for complete engine disassembly, inspection, and repair. This procedure can be varied to accommodate individual
requirements for disassembly and repair.
Clean all parts thoroughly as the engine is disassembled. Only clean parts can accurately be inspected
and gauged for wear or damage. There are many commercially available cleaners that will quickly remove oil
and grime from engine parts. When such a cleaner is
used, follow the manufacturer’s instructions and safety
precautions carefully. Particular attention should be
given to commercial cleaners compatibility with plastic
parts.
Make sure that the cleaner is wiped off of engine parts
and not allowed to air dry as some cleaners leave a
residue on parts which can affect engine lubrication.
Refer to the appropriate Parts Manual to ensure the
correct replacement parts are ordered.
1. Drain Fuel From Tank*
2. Remove Engine From Equipment
5. Remove Choke/Carburetor*
6. Remove Carburetor Mount/Reed Plate, And
Fuel Tank
7. Remove Muffler*
8. Remove Clutch
9. Remove Starter Housing
10. Remove Ignition Module
11. Remove Flywheel
12. Remove Fan Shroud
13. Remove Spark Plug*, Cylinder, And
Piston/Connecting Rod
14. Remove Crankshaft; Disassemble Crankcase
* On some units, these can be removed and reinstalled without removing the engine from its normal
operating installation.
3
3. Remove Styling Cover
4. Remove Air Filter*
NOTE: Only disassemble the engine to the extent nec-
essary to make the desired repairs.
3-5
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