Briggs & Stratton 090600 User manual

FORWARD
This manual was written to assist engine technicians and service personnel with the repair and
maintenance procedures for Briggs & Stratton® engines. It assumes that persons using this manual have
been properly trained in and are familiar with the servicing procedures for these products, including the
proper use of required tools and safety equipment and the application of appropriate safety practices.
Persons untrained or unfamiliar with these procedures or products should not attempt to perform such
work.
Proper maintenance and repair is important to safe, reliable operation of all engines and engine-driven
systems. The troubleshooting, testing, maintenance, and repair procedures described in this manual are
appropriate for the Briggs & Stratton® engines described herein. Alternative methods or procedures may
pose risk to personal safety and the safety and/or reliability of the engine and are not endorsed or
recommended by Briggs & Stratton.
All information, illustrations, and specifications contained in this manual were based on the data available
at the time of publication. Briggs & Stratton Corporation reserves the right to change, alter, or otherwise
improve the product or the product manuals at any time without prior notice.
Briggs & Stratton offers two complementary publications to enhance understanding of engine technology,
maintenance, and repair. (Neither publication, however, is a substitution for a recognized training program
for engine technicians.)
• For consumers, Small Engine Care & Repair (p/n 274041) provides a comprehensive overview of how
small air-cooled engines work, basic troubleshooting, and step-by-step maintenance procedures.
• For engine technicians and consumers alike, an in-depth study of engine theory and operation can be
found in the textbook Small Engines (p/n CE8020).
Both publications can be purchased at BRIGGSandSTRATTON.COM or through a local Authorized Briggs
& Stratton Service Dealer.
Copyright © 2010 Briggs & Stratton Corporation
All rights reserved.
No part of this manual may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying or recording by any information storage and retrieval system, without
prior written permission from Briggs & Stratton Corporation.

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This engine repair manual includes the following
engine models:
• MODEL 090600
• MODEL 100600
• MODEL 100800

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SECTION 1 - Safety, Maintenance and Adjustments
SECTION 2 - Troubleshooting
SECTION 3 - Exhaust Systems
SECTION 5 - Governor Systems
SECTION 6 - Cylinder Heads and Valves
SECTION 7 - Starters
SECTION 8 - Lubrication Systems
SECTION 9 - Cylinders, Covers and Sumps
SECTION 10 - Crankshafts, Camshafts, Balancing Systems and Gear Reductions
SECTION 11 - Pistons, Rings and Connecting Rods
SECTION 12 - Engine Specifications
SECTION 4 - Fuel Systems and Carburetion
maintocIntek.fm Page 1 Friday, January 15, 2010 2:29 PM

THISPROPER SERVICE AND REPAIR IS IMPORTANT
TO THE SAFE, ECONOMICAL AND RELIABLE
maintocIntek.fm Page 2 Friday, January 15, 2010 2:29 PM

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SECTION 1 - SAFETY, MAINTENANCE AND ADJUSTMENTS
SAFETY INFORMATION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4
ENGINE MAINTENANCE - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 7
FUEL AND OIL RECOMMENDATIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 7
MAINTENANCE CHART - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 7
OIL CHANGE- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 8
AIR FILTER - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 8
SPARK PLUG - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 8
COOLING SYSTEM - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 9
CHARGING BATTERY - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 9
COMBUSTION CHAMBER - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -10
ENGINE ADJUSTMENTS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -10
THROTTLE CABLE ADJUSTMENT - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -10
GOVERNOR ADJUSTMENTS- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -10
ADJUST VALVE CLEARANCE - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -12
ADJUST READYSTART® CHOKE LINK - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -12
ADJUST ARMATURE AIR GAP- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -13
ADJUST ALTERNATOR AIR GAP - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -14
FLYWHEEL BRAKE - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -15

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SAFETY INFORMATION
This repair manual contains safety information
that is designed to:
• Make you aware of hazards associated
with engines.
• Inform you of the risk of injury associated
with those hazards.
• Tell you how to avoid or reduce the risk of
injury.
Signal Words in Safety Messages
The safety alert symbol is used to identify
safety information about hazards that can result
in personal injury.
A signal word (DANGER, WARNING, or CAUTION)
is used with the alert symbol to indicate the
likelihood and the potential severity of injury. In
addition, a hazard symbol may be used to
represent the type of hazard.
DANGER indicates a hazard which, if not
avoided, will result in death or serious
injury.
WARNING indicates a hazard which, if
not avoided, could result in death or
serious injury.
CAUTION indicates a hazard which, if
not avoided, could result in minor or
moderate injury.
NOTICE indicates a situation that could
result in damage to the product.
Prior to work, read and understand the section(s)
of this manual that pertain to the job. Follow all
safety warnings.
• Always use fresh gasoline. Stale fuel can
cause gum deposits in the carburetor
and cause leakage, flow restrictions, or
other problems.
• Check fuel lines and fittings frequently for
cracks or leaks and replace if necessary.
Hazard Symbols and Meanings
WARNING
Before attempting to service this equipment,
read and understand this manual and the
operating instructions of the engine and the
equipment it powers.
Failure to follow instructions could result in
property damage, serious injury (including
paralysis) or even death.
FIRE EXPLOSION ELECTRIC
SHOCK
EXPLOSIVE
PRESSURE
HOT
SURFACE GOGGLES
ENTANGLEMENT KICKBACK AMPUTATION
TOXIC
FUMES
READ
MANUAL
CHEMICAL
BURNS
WARNING
Battery posts, terminals, and related accesso-
ries contain lead and lead compounds - chem-
icals known to the State of California to cause
cancer and reproductive harm. Wash hands
after handling.

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WARNING
Certain components in this product and its
related accessories contain chemicals known
to the State of California to cause cancer, birth
defects, or other reproductive harm. Wash
hands after handling.
WARNING
Briggs & Stratton does not approve or autho-
rize the use of these engines on 3-wheel All
Terrain Vehicles (ATVs), motor bikes, fun/rec-
reational go-karts, aircraft products, or vehi-
cles intended for use in competitive events.
Use of these engines in such applications
could result in property damage, serious injury
(including paralysis), or even death.
WARNING
The engine exhaust from this product contains
chemicals known the State of California to
cause cancer, birth defects, and other repro-
ductive harm.
WARNING
Running engines produce heat.
Severe burns can occur on contact.
• Allow muffler, engine cylinder fins, and
radiator to cool before touching.
• Remove accumulated combustibles from
muffler area and cylinder area.
• It is a violation of California Public
Resource Code, Section 4442, to use or
operate the engine on any forest-covered,
brush-covered, or grass-covered land
unless the exhaust system is equipped
with a spark arrester, as defined in Section
4442, maintained in effective working
order. Other States and Federal jurisdic-
tions may have similar laws. Contact the
original equipment manufacturer, retailer,
or dealer to obtain spark arrester
designed for the exhaust system installed
on this engine.
WARNING
Fuel and its vapors are extremely flam-
mable and explosive.
Fire or explosion can cause severe
burns or death.
When adding fuel:
• Turn engine OFF and let engine cool for at
least 2 minutes before removing the fuel
cap.
• Fill fuel tank outdoors or in a well-venti-
lated area.
• Do not overfill fuel tank. To allow for
expansion of the gasoline, do not fill above
the bottom of the fuel tank neck.
• Keep gasoline away from sparks, open
flames, pilot lights, heat and other ignition
sources.
• Check fuel lines, tank, cap, and fittings fre-
quently for cracks or leaks. Replace if nec-
essary.
• If fuel spills, wait until it evaporates before
starting engine.
When starting engine:
• Make sure spark plug, muffler, fuel cap,
and air cleaner are in place.
• Do not crank engine with spark plug
removed.
• If fuel spills, wait until it evaporates before
starting engine.
• If engine floods, set choke (if equipped) to
OPEN/RUN position. Place throttle (if
equipped) in FAST and crank until engine
starts.
When operating equipment:
• Do not tip engine or equipment at an
angle which would cause fuel to spill.
• Do not choke carburetor to stop engine.
• Never start or run the engine with the air
cleaner assembly (if equipped) or the air
filter (if equipped) removed.
When changing oil:
• If you drain the oil from the top oil fill tube,
the fuel tank must be empty or fuel can
leak out and result in a fire or explosion.
When transporting equipment:
• Transport with fuel tank empty or with fuel
shut-off valve set to OFF.
When storing gasoline or equipment with
fuel in the tank:
• Store away from furnaces, stoves, water
heaters, or other appliances that have a
pilot light or other ignition source because
they can ignite gasoline vapors.

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WARNING
Unintentional sparking can result in fire
or electrical shock.
Unintentional start-up can result in
entanglement, traumatic amputation, or
severe lacerations.
Before performing adjustments or repairs:
• Disconnect spark plug wire and keep it
away from spark plug.
• Disconnect the negative (-) battery termi-
nal.
When testing for spark:
• Use approved spark plug tester.
• Do not check for spark with spark plug
removed.
WARNING
Engines give off carbon monoxide, an
odorless, colorless, poison gas.
Breathing carbon monoxide can cause
nausea, fainting, or death.
• Start and run engine outdoors.
• Do not start or run engine in an enclosed
area, even if doors and windows are open.
WARNING
Starting engine creates sparking.
Sparking can ignite nearby flammable
gases.
Explosion and fire could result.
• If there is a natural or LP gas leak in the
area, do not start engine.
• Do not use pressurized starting fluids
because vapors are flammable.
WARNING
Rotating parts can contact or entangle
hands, feet, hair, clothing, or accesso-
ries.
Traumatic amputation or severe lacera-
tions can result.
• Operate equipment with guards in place.
• Keep hands and feet away from rotating
parts.
• Tie up long hair and remove jewelry.
• Do not wear loose-fitting clothing, dangling
drawstrings, or items that could become
entangled in the equipment.
WARNING
Charging batteries produce hydrogen
gas. Do not store or charge a battery
near an open flame or device that uti-
lizes a pilot light or can create a spark.
WARNING
Damaged, worn, or loose fuel compo-
nents can leak fuel. Explosion or fire
could result.
• All fuel components should be in good
condition and properly maintained.
• Repairs should only be made with factory
approved parts.
• Repair work should be done by a qualified
technician.
• Flexible supply lines should be checked
regularly to make sure they are in good
condition.
WARNING
Rapid retraction of starter cord (kick-
back) will pull hand and arm toward
engine faster than you can let go.
Broken bones, fractures, bruises, or
sprains could result.
• When starting engine, pull the starter cord
slowly until resistance is felt and then pull
rapidly to avoid kickback.
• Remove all external equipment/engine
loads before starting engine.
• Direct-coupled equipment components,
such as but not limited to blades, impel-
lers, pulleys, and sprockets, must be
securely attached.
WARNING
Prolonged or repeated contact with used
motor oil could cause injury.
• Used motor oil has been shown to cause
skin cancer in certain laboratory animals.
• Thoroughly wash exposed areas with
soap and water.

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ENGINE MAINTENANCE
Fuel and Oil Recommendations
Fuel must meet these requirements:
• Clean, fresh, unleaded gasoline.
• A minimum of 87 octane / 87 AKI
(90 RON).
• Gasoline with up to 10% ethanol
(gasahol) or up to 15% MTBE (methyl
tertiary butyl ether) is acceptable.
NOTICE: Do not use unapproved gasoline, such
as E85. Do not mix oil in gasoline or modify the
engine to run on alternate fuels. This will damage
the engine components and void the engine
warranty.
To protect the fuel system from gum formation,
mix a fuel stabilizer into the fuel. All fuel is not the
same. If starting or performance problems occur,
change fuel providers or change brands. This
engine is certified to operate on gasoline. The
emissions control system for this engine is EM
(Engine Modifications).
High Altitude
At altitudes over 5,000 feet (1524 meters), a
minimum 85 octane / 85 AKI (89 RON) gasoline
is acceptable. To remain emissions compliant,
high altitude adjustment is required. Operation
without this adjustment will cause decreased
performance, increased fuel consumption, and
increased emissions.
Operation of the engine at altitudes below 2,500
feet (762 meters) with the high altitude kit is not
recommended.
Fresh Start®Fuel Cap
Some engines are equipped with a Fresh Start®
fuel cap. The Fresh Start fuel cap is designed to
hold a cartridge (sold separately) that contains
fuel stabilizer.
Oil must meet these requirements:
• Briggs & Stratton warranty certified oils
are recommended for best performance.
• Other high-quality detergent oils are
acceptable if classified for service SF,
SG, SH, SJ or higher.
• Do not use special additives.
Outdoor temperatures determine the proper oil
viscosity for the engine.
Use the chart (Figure 1-1) to select the best
viscosity for the outdoor temperature range
expected.
Figure 1 - 1
MAINTENANCE CHART
* In dusty conditions or when airborne debris is
present, clean more often.
First 5 Hours
• Change oil
Every 8 Hours or Daily
• Check engine oil level
• Clean area around muffler and
controls
• Clean finger guard
Every 25 Hours or Annually
• Clean air filter*
• Clean pre-cleaner*
Every 50 Hours or Annually
• Change engine oil
• Check muffler and spark arrester
Annually
• Replace air filter
• Replace pre-cleaner
• Replace spark plug
• Replace fuel filter
• Clean air cooling system*

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Oil Change
Change oil after the first 5 hours of operation.
After that, change oil after every 50 hours of
operation. Change oil more often if engine is
operated in dirty or dusty conditions, under
heavy loads, or in high ambient temperatures.
1. Remove oil drain plug from side or bottom
of engine and drain oil while the engine is
still warm.
2. Install drain plug.
3. Fill crankcase with correct amount of new
oil.
4. Start engine and run at idle for a minute or
so.
5. Shut engine off and wait for oil to settle
back into the cylinder.
6. Check dipstick. If necessary, add more oil
slowly to bring level to FULL mark on
dipstick.
Air Filter
A correctly serviced air filter protects internal
engine parts from airborne dirt and dust. Poor
filter maintenance will allow dirt and dust to be
drawn into the engine, causing wear to the intake
system and contamination of the oil. Dirt in the oil
forms an abrasive mixture which wears down
moving parts.
NOTE: Do not use pressurized air or solvents to
clean the filter. Pressurized air can damage the
filter and solvents will dissolve the filter.
1. Remove air cleaner cover (Aand B,
Figure 1-2). Remove pre-cleaner (C) from
cartridge (D).
2. Gently tap air filter cartridge on a hard
surface to loosen debris. Replace
cartridge if very dirty.
3. Wash foam pre-cleaner in warm, soapy
water, then rinse and allow to air dry.
4. Reassemble the air cleaner system.
Figure 1 - 2
Spark Plug
The spark plug should be replaced every year.
NOTE: In some areas, local law requires using
resistor spark plugs to suppress radio frequency
interference.
1. Disconnect spark plug wire.
2. Remove and inspect spark plug for wear
and damage. Replace spark plug if
electrodes are burned away, or the
porcelain is cracked.
WARNING
Fuel and its vapors are extremely flam-
mable and explosive.
Fire or explosion can cause severe
burns or death.
• Never start or run the engine with the air
cleaner assembly or the air filter removed.
NOTICE
Spark plugs have different thread lengths
and heat ranges. When changing a spark
plug, use only the specified replacement,
otherwise engine damage could occur.

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3. Do not sand-blast or bead-blast the spark
plug. Clean by scraping or wire brushing,
and then washing in a commercial solvent.
4. Using a wire gage, check and set the gap
(A, Figure 1-3) per Section 12 - Engine
Specifications.
Figure 1 - 3
5. Re-install spark plug and torque to values
listed in Section 12 - Engine
Specifications.
6. Connect spark plug wire.
Cooling System
Dirt or debris can restrict air flow and cause the
engine to overheat, resulting in poor
performance and reduced engine life. Continued
operation with a clogged cooling system can
cause severe overheating and possible engine
damage. Clean these areas (A, Figure 1-4)
yearly or more often when dust or airborne
debris is present.
NOTICE: Do not use water to clean the engine.
Water could contaminate the fuel system. Use a
brush or dry cloth to clean the engine.
Figure 1 - 4
Charging Battery
1. Clean the battery of all dirt and corrosion.
2. Clean, then lightly grease the terminals.
3. Bring the battery to full charge using a
taper charge (automatically reduces
charge rate).
NOTE: Do not exceed a charge rate of 1/10
ampere for every ampere of battery rating.
Consult the battery manufacturer for maximum
charge recommendations.
NOTE: If the battery gets hot to the touch or is
spitting acid (gassing) excessively, unplug the
charger periodically.
4. With the battery fully charged, check the
specific gravity readings of each cell with a
temperature-compensated Battery
Hydrometer (Figure 1-5). All readings
should be above 1.250 (compensating for
temperature). If the readings vary by
0.050 or if all cells read less than 1.225,
replace the battery.
Figure 1 - 5
WARNING
Running engines produce heat.
Severe burns can occur on contact.
• Allow muffler, engine cylinder fins, and radiator
to cool before touching.
• Remove accumulated combustibles from muf-
fler area and cylinder area.

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Combustion Chamber
Remove combustion chamber deposits every
500 hours or whenever the cylinder head is
removed.
With the piston at Top Dead Center (TDC),
scrape deposits from top of piston and upper
bore with a plastic scraper.
Remove the loosened deposits from around the
top ring land area using compressed air or a
shop vacuum and a soft bristle brush.
NOTE: Use care to prevent debris from entering
the valve lever or oil return cavities in cylinder.
Do not damage bore, top of piston, cylinder
head, or gasket mounting surfaces.
It is not necessary to remove the discoloration
marks on the piston, valves, and/or cylinder
head. These marks are normal and will not affect
engine operation.
ENGINE ADJUSTMENTS
Throttle Cable Adjustment
The remote control wire should measure 2.125”
(54 mm) when extended outside the casing
(A, Figure 1-6). After installation, the travel (B) of
the remote control wire must be at least 1.375”
(35 mm). If the travel of the remote control wire
does not reach the minimum distance, use the
following procedure to adjust the cable:
1. Loosen casing clamp screw (C).
2. Move throttle lever to FAST position.
3. Move casing in direction of arrow (D) until
slack is removed.
4. Tighten casing clamp screw. Torque to
values listed in Section 12 - Engine
Specifications.
Figure 1 - 6
Governor Adjustments
A complete governor system adjustment
includes a static adjustment, engine warm-up,
and top no-load adjustment. Be sure to complete
all steps.
Static Adjustment
1. Loosen nut (A, Figure 1-7) until governor
lever (B) moves freely from governor
crank (C).
2. Move throttle linkage (D) until throttle plate
(E) is wide open.

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NOTE: Choke valve (F) closes when opening the
throttle plate.
3. While holding linkage, tighten governor
lever nut. Torque to values listed in
Section 12 - Engine Specifications.
4. Before starting engine, manually actuate
throttle linkage to check for binding.
Figure 1 - 7
Top No-Load Adjustment
1. Start engine and run at idle speed until it
reaches operating temperature.
2. Place throttle lever (G, Figure 1-8) in FAST
position.
3. Using Tachometer #19200 or #19389 (H),
and Tang Bender #19229 or #19352 (J),
bend spring tang (K) to obtain correct top
no-load RPM.
NOTE: Correct top no-load RPM for each model-
type-trim can be found in the engine replacement
data on Briggs & Stratton websites.
Figure 1 - 8

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Adjust Valve Clearance
NOTE: Check valve clearance while the engine
is cold.
1. Insert a narrow gauge such as a
screwdriver, rod, or pencil (A, Figure 1-9)
into the spark plug hole (B) until it touches
the piston (C). Cut away view is shown.
2. Observe the movement of the gauge and
turn the flywheel (D) clockwise past top
dead center on the compression stroke
until the piston has moved down the bore
0.25 in. (6.4 mm).
3. Valve clearance is checked by placing a
feeler gauge (E) between the lever arm
adjusting screw (F) and the valve cap (G).
4. Loosen the adjusting screw nut (H) with a
wrench.
5. Using an allen wrench, turn the adjusting
screw (F) to obtain the correct clearance.
6. Tighten the adjusting screw nut (H) to the
torque values listed in Section 12 - Engine
Specifications.
7. Recheck clearance after tightening nut.
Figure 1 - 9
Adjust ReadyStart® Choke Link
Perform this adjustment while the engine is cold.
1. Using pliers, bend adjusting loop (A,
Figure 1-10) on choke link (B) until choke
lever gap (C) measures 0.000 - 0.060 in.
(0.000 - 1.52 mm). When properly
adjusted, the choke plate (D) will be fully
closed. Reshape wire to keep it parallel
(E) after adjusting loop.
Figure 1 - 10

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Adjust Armature Air Gap
1. Disconnect spark plug boot (A, Figure 1-
11) and secure away from spark plug.
2. Loosen screw (B) and stud (C).
3. Slide armature (D) away from flywheel.
4. Tighten stud to secure armature.
5. Line up flywheel magnets (E) with
armature.
6. Insert a strip of gauge material (F)
(0.006 - 0.014 in. or 0.15 - 0.36 mm)
between flywheel magnet and both legs of
armature.
7. Loosen stud and allow magnet to pull
armature against gauge (G).
8. Tighten fasteners and torque to values
listed in Section 12 - Engine
Specifications.
9. Rotate flywheel to remove gauge.
Figure 1 - 11

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Adjust Alternator Air Gap
1. Remove spark plug.
2. Loosen alternator screws (A, Figure 1-12).
and slide alternator (B) away from
flywheel.
3. Tighten one screw to secure alternator.
4. Line up flywheel magnet (D) with
alternator.
5. Insert a strip of gauge material (C)
(0.006-0.014 in. or 0.15-0.36 mm)
between flywheel magnet and both legs of
alternator.
6. Loosen screw and allow magnet to pull
alternator against gauge.
7. Tighten fasteners and torque to values
listed in Section 12 - Engine
Specifications.
8. Rotate flywheel to remove gauge.
Figure 1 - 12

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Flywheel Brake
The flywheel brake is part of the safety control
system required for some applications. While
running at the FAST speed position, the flywheel
brake MUST stop the engine within three
seconds when the operator releases the
equipment safety control.
Test Brake Torque
1. Disconnect spark plug wire.
2. Remove static guard/rewind assembly.
3. Unscrew and remove fuel tank.
4. Remove dipstick and oil fill tube.
5. Unscrew and remove blower housing.
Figure 1 - 13
6. Using a torque wrench (A, Figure 1-13)
and socket to fit the flywheel nut, turn
flywheel clockwise with brake engaged.
While turning at a steady rate, torque
value should be 26 lb.-in. (3 Nm) or higher.
7. If reading is low, check thickness of brake
pad (B). Replace brake assembly if
thickness is less than 0.090” (2.28 mm).
8. If brake pad thickness is acceptable,
adjust control cable to position pad closer
to flywheel when safety control is in RUN
position.Repeat Step 6.
9. Replace brake assembly if correct
adjustment cannot be made.

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Remove Flywheel Brake
1. Disconnect and remove spring from brake
anchor.
2. Disconnect safety control cable from brake
assembly.
3. Loosen brake screw (A, Figure 1-14) but
do not remove.
4. Rotate bracket to relieve tension on screw
(B) and remove, then remove screw (A).
5. Press stop switch tang to disconnect stop
wire, then remove brake assembly.
6. Disconnect wires on interlock switch, if
equipped.
Figure 1 - 14
Install Flywheel Brake
1. Install stop switch wire and bend end of
wire 90°. Install wires on interlock switch, if
equipped.
2. Install brake assembly on cylinder and
torque mounting screws to values listed in
Section 12 - Engine Specifications.
3. Connect safety control cable and install
brake spring.
4. Actuate brake system to ensure proper
movement, then test brake torque as
previously described.
5. Install blower housing, oil fill tube, dipstick,
fuel tank, and static guard/rewind
assembly. Torque all screws to values
listed in Section 12 - Engine
Specifications.

17
1
2
SECTION 2 - TROUBLESHOOTING
SYSTEMS CHECK - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 18
CHECK IGNITION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 18
CHECK CARBURETION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19
CHECK COMPRESSION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 19
ELECTRICAL SYSTEMS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 20
EQUIPMENT USED FOR TESTING - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 20
ALTERNATOR TESTING - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 21
STARTER MOTOR TESTING- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 22
BATTERY TESTING - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 23

18
1
2
SYSTEMS CHECK
Most complaints concerning engine operation
can be classified as one or a combination of the
following:
• Will not start
• Hard starting
• Lack of power
• Runs rough
• Vibration
• Overheating
• High oil consumption
What appears to be a problem with the engine
may actually be the fault of the equipment.
Following is a list of some common engine
symptoms and their relationship to equipment
problems.
No Start - Hard Start
• Loose belt or blade
• Cranking under load
• Misadjusted controls
• Interlock system malfunction
Engine Will Not Stop
• Equipment stop switch not functioning
• Engine ground wire damaged or
disconnected
Vibration
• Bent cutter blades
• Loose spindles and couplings
• Bent/broken deck or weldments
• Bent crankshaft
• Loose equipment mounting bolts
• Damaged or worn belts and pulleys
• Out of balance impeller
Power Loss
• Bind or drag in moving parts of
equipment
• Grass build-up under deck
• No lubrication in equipment gear box
• Excessive belt tension
Once equipment sources are ruled out, the
cause for most of these symptoms can be
determined by performing a systems check in the
following order:
1. Ignition
2. Carburetion
3. Compression
This check-up can usually be done in a matter of
minutes and is the quickest and surest method of
determining the cause of such problems.
1) Check Ignition
Engine Stopped
With spark plug installed, attach Ignition Tester
#19368 to spark plug lead and ground the other
end of the tester (Figure 2-1). Pull the starter
rope or activate the electric starter (if equipped).
If spark jumps the tester gap, you may assume
the ignition system is functioning satisfactorily.
Figure 2 - 1
Engine Running
If engine runs but misses during operation, a
quick check to determine whether the ignition is
at fault can be made by installing Ignition Tester
#19368 between the spark plug lead and spark
plug (Figure 2-2). If spark is good but engine
misses, install a new spark plug.