Vanguard OHV V-Twin, 290000, 300000, 350000, 380000 User Manual
...
For Briggs & Stratton Discount Parts Call 606-678-9623 or 606-561-4983
TABLE OF CONTENTS
SAFETY, MAINTENANCE AND ADJUSTMENTS Section 1. . . . . . . . . . . . . . . . . .
TROUBLESHOOTING Section 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ENGINE DISASSEMBLY Section 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FUEL SYSTEMS AND CARBURETION Section 4. . . . . . . . . . . . . . . . . . . . . . . . . .
GOVERNOR Section 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CYLINDER HEADS AND VALVES Section 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
STARTERS Section 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LUBRICATION SYSTEMS Section 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CYLINDERS AND CRANKCASE COVERS/SUMPS Section 9. . . . . . . . . . . . . . .
CRANKSHAFTS AND CAMSHAFTS Section 10. . . . . . . . . . . . . . . . . . . . . . . . . . . .
PISTONS, RINGS AND CONNECTING RODS Section 11. . . . . . . . . . . . . . . . . . .
ENGINE ASSEMBLY Section 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ENGINE SPECIFICATIONS Section 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Section 1
Safety, Maintenance and Adjustments
Page
AIR CLEANER SERVICE 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Round Air Cleaner 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Square Air Cleaner 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cyclonic Air Cleaner 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ARMATURE AIR GAP ADJUSTMENT 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BRIGGS & STRATTON NUMERICAL IDENTIFICATION SYSTEM 6. . . . . . . . . . . . . . . . . . . . . . . . .
CARBURETOR ADJUSTMENTS 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Models 290000 – 350000 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performance ControlE Engines 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Models 351400, 380400, 351700, 380700 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHOKE CONTROL ADJUSTMENT 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COMBUSTION CHAMBER DEPOSITS 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COOLING SYSTEM CLEANING 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CRANKCASE OIL 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
FUEL AND OIL RECOMMENDATIONS 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Recommendations 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Recommendations 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GOVERNOR ADJUSTMENTS 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Static Governor Adjustment 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dynamic Governor Adjustment 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IN THE INTEREST OF SAFETY 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAINTENANCE AND ADJUSTMENTS SCHEDULE 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OIL COOLER 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OVERHAUL PROCEDURE 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disassemble 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inspection and Repairs 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reassemble 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPARK PLUGS 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPEED CONTROL WIRE ADJUSTMENT 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TUNE UP PROCEDURE 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VALVE CLEARANCE ADJUSTMENT 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
1
IN THE INTEREST OF SAFETY
DANGER
FOLLOW INSTRUCTIONS
CAREFULLY !
• Before attempting to service this equipment,
read and understand this manual and the
operating instructions.
• Failure to follow instructions could result in
DEATH, SERIOUS INJURY (including paralysis) or property damage.
* Briggs & Stratton does not necessarily know what
equipment this engine will power. For that reason,
carefully read and understand the operating instructions for the equipment your engine is powering.
CAUTION indicates a hazard that, if not
avoided, might result in minor or moderate injury.
CAUTION, when used without the alert symbol, in-
dicates a situation that could result in damage to
the engine.
NOTE: A NOTE is used to inform you of a method,
reference or procedure that could assist
with specific operations or procedures.
HAZARD SYMBOLS AND MEANINGS
Fire
Explosion
Hot Surface
THE OPERATING, MAINTENANCE &
REPAIR INSTRUCTIONS CONTAIN
SAFETY INFORMATION TO:
• Make you aware of hazards associated with
engines
• Inform you of the risk of injury associated with
those hazards, and
• Tell you how to avoid or reduce the risk of injury.
SAFETY ALERT SYMBOL
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 that, if not
avoided, will result in death or serious injury.
Shock
Eye Protection
Required
INTERNATIONAL SYMBOLS AND MEANINGS
Safety Alert
Choke Start Position
Toxic Fumes
Flying Objects
Oil
Moving Parts
Kickback
Read Operator’s
Manual
Stop
WARNING indicates a hazard that, if not
avoided, could result in death or serious injury.
2
Fuel
Fuel Shutoff
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WARNING
Gasoline and its vapors are extremely
flammable and explosive.
Fire or explosion can cause severe
burns or death.
WHEN ADDING FUEL
• Turn engine OFF and let engine cool at least 2
minutes before removing gas cap.
• Fill fuel tank outdoors or in a well-ventilated
area. Keep gasoline and its vapors away from
sparks, open flames, pilot lights, heat, and
other ignition sources.
• Do not overfill fuel tank. Fill tank to
approximately 1-1/2 inches below top of neck
to allow for fuel expansion.
• Check fuel lines, tank, cap, and fittings
frequently for cracks or leaks. Replace if
necessary.
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 and the
vapors dissipate before starting engine.
• If engine floods, set choke to OPEN/RUN
position, place throttle in FAST position.
Crank until engine starts.
WHEN OPERATING EQUIPMENT
• Do not tip engine or equipment at an angle
that causes gasoline to spill.
• Do not choke carburetor to stop engine.
WHEN TRANSPORTING EQUIPMENT
• Transport with fuel tank EMPTY or with fuel
shut-off valve OFF.
WHEN STORING GASOLINE OR EQUIPMENT
WITH FUEL IN TANK
• Store away from furnaces, stoves, water
heaters or other appliances that have pilot
light or other ignition source. These can ignite
gasoline vapors.
WARNING
Kerosene and its vapors are
extremely flammable, and should
be handled with the same
precautions as gasoline.
WARNING
Unintentional sparking can result
in fire or electric shock.
Unintentional start-up can result in
entanglement, traumatic amputation, or laceration.
BEFORE PERFORMING ADJUSTMENTS
OR REPAIRS
• Disconnect spark plug wire and keep it away
from spark plug.
• Disconnect battery at negative terminal (only
engines with electric start).
WHEN TESTING FOR SPARK
• Use approved spark plug tester.
• DO NOT check for spark with spark plug
removed.
WARNING
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.
Replace damaged or leaking
components.
3
1
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 enclosed area,
even if doors or windows are open.
• Inhalation of high concentrations of vapor,
even for short periods can cause unconsciousness or might prove fatal.
• Inhalation may cause irritation to the nose and
throat, headache, nausea vomiting, dizziness,
and drowsiness.
• Unconsciousness or asphyxiation may result
in poorly ventilated areas or confined spaces.
WARNING
Running engines produce heat.
Engine parts, especially muffler,
become extremely hot.
Severe thermal burns can occur
on contact.
Combustible debris, such as
leaves, grass, brush, etc. can
catch fire.
• Allow muffler, engine cylinder and fins to cool
before touching.
• Remove accumulated combustibles from
muffler area and cylinder area.
• Install and maintain in working order a spark
arrester before using equipment on forestcovered, grass-covered, brush-covered
unimproved land. The state of California
requires this (Section 4442 of the California
Public Resources Code). Other states may
have similar laws. Federal laws apply on
federal land.
WARNING
Rotating parts can contact or
entangle hands, feet, hair, clothing,
or accessories.
Traumatic amputation or severe
laceration 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 caught.
WARNING
Rapid retraction of starter cord
(kickback) 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 cord slowly until
resistance is felt, then pull rapidly.
• Remove all external equipment/engine loads
before starting engine.
• Direct coupled equipment components such
as, but not limited to, blades, impellors,
pulleys, sprockets, etc., must be securely
attached.
WARNING
The engine exhaust from this product
contains chemicals known to the State
of California to cause cancer, birth
defects, or other reproductive harm.
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Additional Precautions
Before working on the engine, read and understand
the applicable sections of this manual. Follow all
safety warnings. Death, personal injury and/or property damage may occur unless service instructions
are followed carefully.
DO NOT store, spill, or use gasoline near an open
flame, or near an appliance like a stove, furnace, or
water heater that uses a pilot light or creates a spark.
DO NOT refuel indoors or in an unventilated area.
DO NOT operate or tip engine/equipment at an
angle that causes gasoline spillage.
DO NOT operate engine if gasoline is spilled, when
smell of gasoline is present, or when other explosive
conditions exist. (Move equipment away from spill.
Avoid ignition until gasoline has evaporated.)
DO NOT transport engine with fuel in tank or fuel
shut-off valve open.
DO NOT choke carburetor to stop engine, especially
in an enclosed vehicle. (Gradually reduce engine
speed before stopping.)
DO NOT tamper with governor springs, links or other
parts to increase engine speed. (Run engine at speed
set for equipment manufacturer.)
DO NOT check for spark with spark plug removed.
(Use an approved tester.)
DO NOT run engine with blower housing or other
safety shields removed.
DO NOT crank engine with spark plug removed. (If
engine is flooded, place throttle in FAST position and
crank until engine starts.)
DO NOT strike flywheel with a hammer or hard object.
This could cause the flywheel to shatter in operation.
(Use only Briggs & Stratton approved tools and procedures to remove the flywheel.)
DO NOT operate engine without a muffler. (Inspect
periodically and replace if worn or leaking. If engine
is equipped with muffler deflector, inspect periodically
and replace if necessary. Replacement parts must be
same as on original equipment.)
DO NOT operate engine with grass, leaves or other
combustible material accumulated in the muffler
area.
DO NOT touch hot muffler, cylinder, or fins which can
cause burns.
DO NOT start engine with air cleaner or air cleaner
cover removed.
DO NOT attempt to start engine with cutting blade
loose or removed. (Blade must be tight, otherwise
kickback may occur.)
DO NOT remove fuel tank cap or fill the fuel tank
while the engine is hot or running. DO NOT refuel indoors or in an unventilated area. Allow the engine to
cool at least 2 minutes before refueling.
WEAR suitable eye protection (safety glasses,
goggles or face shield) when performing repair procedures.
PREVENT ACCIDENTAL STARTING by disconnecting spark plug wire from spark plug when servicing engine or equipment. Disconnect negative wire
from battery terminal if equipped with electric starting system.
USE ONLY genuine Briggs & Stratton parts or their
equivalent. The use of non-equivalent replacement
parts may damage the engine.
GASEOUS FUEL ENGINES – Check fuel lines and
fittings frequently for cracks or leaks. Replace as
necessary.
5
BRIGGS & STRATTON NUMERICAL IDENTIFICATION SYSTEM
YOUR KEY TO THE WORLD'S FINEST ENGINES
This chart explains the unique Briggs & Stratton numerical model designation system. It is possible to determine most of the
important mechanical features of the engine by merely knowing the model number. Here is how it works:
A. The first one or two digits indicate the approximate CUBIC INCH DISPLACEMENT.
B. The first digit after the displacement indicates the BASIC DESIGN SERIES, relating to cylinder
construction, ignition, general configuration, etc.
C. The second digit after the displacement indicates ORIENTATION OF CRANKSHAFT.
D. The third digit after the displacement indicates TYPE OF BEARINGS, and whether or not the
engine is equipped with REDUCTION GEAR or AUXILIARY DRIVE.
E. The last digit indicates the TYPE OF STARTER.
BRIGGS & STRATTON MODEL NUMBERING SYSTEM
FIRST DIGIT
AFTER DISPLACEMENT
A B C D E
CUBIC INCH
DISPLACEMENT
ă6
ă8
ă9
10
11
12
13
16
18
19
20
21
22
23
24
25
28
29
30
31
32
35
38
40
42
43
44
46
47
52
54
58
EXAMPLE - To identify Model 303447:
30 3 4 4 7
30 Cubic Inch Design Series 3 Horizontal Shaft Ball Bearing
BASIC
DESIGN SERIES
0
1
2
3
4
5
6
7
8
9
A to Z
A to G - Horizontal Shaft
H to Z - Vertical Shaft
TYPE 1234Ć01, The type number identifies the engines mechanical parts, color of paint, decals, governed speed, and Original
Equipment Manufacturer.
CODE
01061201, The code is the manufacturing date and is read as follows:
YEAR MONTH DAY ASSEMBLY LINE AND MANUFACTURING PLANT
01 06 12 01
Revised 4/04
SECOND DIGIT
AFTER DISPLACEMENT
CRANKSHAFT
ORIENTATION
0 to 4 - Horizontal Shaft
5 to 9 - Vertical Shaft
THIRD DIGIT
AFTER DISPLACEMENT
PTO BEARING,
REDUCTION GEAR,
AUXILIARY DRIVE,
LUBRICATIONă TYPE OF STARTER
0 - Plain Bearing/DU
NonĆFlange Mount
1 - Plain Bearing
Flange Mounting
2 - Sleeve Bearing
Flange Mounting
Splash Lube
3 - Ball Bearing
Flange Mounting
Splash Lube
4 - Ball Bearing
Flange Mounting
Pressure Lubrication
5 - Plain Bearing
Gear Reduction
(6 to 1) CCW Rotation
Flange Mounting
6 - Ball Bearing
Gear Reduction
(2 to 1) CCW Rotation
7 - Plain Bearing
Pressure Lubrication
8 - Plain Bearing
Auxiliary Drive (PTO)
Perpendicular to
Crankshaft
9 - Plain Bearing
Auxiliary Drive
Parallel to Crankshaft
A - Plain Bearing
Pressure Lubrication
Without Oil Filter
Flange Mounting
Pressure Lubrication
FOURTH DIGIT
AFTER DISPLACEMENT
0 - Without Starter
1 - Rope Starter
2 - Rewind Starter
3 - Electric Starter Only
110 or 230 Volt Gear
Drive
4 - Electric Starter/110 or
230 Volt Gear Drive
with Alternator
5 - Electric Starter Only
12 or 24 Volt Gear
Drive
6 - Alternator Only
7 - Electric Starter
12 or 24 Volt Gear
Drive with Alternator
8 - Vertical Pull Starter or
Side Pull Starter
9 - Mechanical Starter
A - Electric Starter
12 or 24 Volt Gear
Drive with Alternator
and Inverter
Electric Starter
12 or 24 Volt Gear Drive
with Alternator
6
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FUEL & OIL RECOMMENDATIONS
Fuel Recommendations
Gasoline Engines
• Use clean, fresh regular unleaded gasoline with a
minimum of 85 octane. Fresh fuel prevents gum
from forming in the fuel system or on essential
carburetor parts. Purchase fuel in a quantity that
can be used within 30 days.
• Do not use gasoline containing Methanol.
• Do not mix oil with gasoline.
• For engine protection use Briggs & Stratton Fuel
Stabilizer #5041 or single use pouch #5058
available from your Authorized Briggs & Stratton
Dealer.
CAUTION: Some fuel, called “oxygenated” or
“reformulated” gasoline, is gasoline blended
with alcohol or ether. Excessive amounts of
these blends can damage the fuel system or
cause performance problems. If any undesirable operating symptoms occur, use gasoline
with a lower percentage of alcohol or ether.
Gaseous Fuel Engines
DANGER
AVOID INJURY! Gaseous fuel
systems should only be worked
on in a very well ventilated area.
• Many state, county and city governments
require that service be performed ONLY
outdoors.
• Have a fan blowing across the engine BEFORE
loosening fuel line connections!
NOTE: Gaseous fueled engines require special
equipment to remain emissions certified.
See a certified gaseous fuel dealer or a
certified OEM dealer for service.
Use clean fuel free of moisture or particulate
material, within the following values:
For propane (LPG) fueled engines, use commercial
grade HD% propane. Recommended fuel has a
minimum fuel energy of 2500 BTU/ft3, maximum
propylene content 5%, butane, heavier gas content
2.5%, minimum propane content 90%.
WARNING
Inline Fuel Filter Service
Replace inline fuel filter yearly or every 100 hours,
whichever occurs first. Replace filter if dirt or water
are present. See illustrated parts list for correct
fuel filter.
AVOID INJURY! Gaseous fueled
equipment is equipped with an automatic safety gas fuel lock-off valve.
• Do not operate gaseous fueled equipment if the
fuel lock-off valve is missing or inoperative.
7
1
Oil Recommendations
Oil has four purposes. It cools, cleans, seals and lubricates. During normal operation, small particles of
metal from the cylinder walls, pistons, bearings and
combustion deposits contaminate the oil. Dust particles from the air also contaminate the oil, forming
an abrasive mixture that can wear internal engine
parts if the oil is not changed regularly. Fresh oil assists in cooling. Old oil gradually thickens and loses
its cooling ability and its lubricating qualities.
Briggs & Stratton OHV V-Twin engines are lubricated with a gear-driven oil pump.
Use a high quality detergent oil classified “For Service SJ or HIGHER” such as Briggs & Stratton 30
weight oil part #100005 or #100028. Detergent oils
keep the engine cleaner and retard the formation of
gum and varnish deposits. Do not use additives with
recommended oils.
**
-20 0
°F
-30
°C
STARTING TEMPERATURE RANGE ANTICIPATED BEFORE NEXT OIL CHANGE
-20 -10 0 10 20 30 40
20 40 60 80 100
32
Air cooled engines run hotter than automotive
engines. Use of multi-viscosity oils (10W-30,
etc.) in ambient temperatures above 40 F
(4C) will result in high oil consumption. If
multi-viscosity oil is used, check oil level more
frequently to prevent any possible engine
damage due to lack of lubrication.
** SAE 30 oil, if used in ambient temperatures
below 40 F (4 C) will result in hard starting
and possible engine damage due to inadequate lubrication.
Synthetic oil meeting ILSAC GF-2, API certification mark and API service symbol with “SJ/
CF ENERGY CONSERVING” rating or higher,
is an acceptable oil at all temperatures.
NOTE: Use of synthetic oil does not alter
the required oil change intervals.
MAINTENANCE & ADJUSTMENTS SCHEDULE
The following maintenance schedule is a general guide. See the Engine Operating & Maintenance Instructions
for details on specific engine models.
25 Hours
or Every
Season
Note #2
Maintenance Schedule
Check oil level *
Change oil
Change oil filter
Clean/Replace air filter pre-cleaner
Clean/Replace air filter cartridge
Clean cooling system
Inspect/clean spark arrester (if used)
Replace or clean spark plugs
Replace in-line fuel filter
Remove combustion chamber deposits
8 Hours
or Daily
* Change oil after the first 5 to 8 hours of operation (break-in period), then after every 50 hours or every season.
NOTE: #1 – Change oil every 25 hours when operating under heavy load or in high temperatures.
50 Hours
or Every
Season
Note #1
100 Hours
or Every
Season
Note #2
Note #2
500
Hours
NOTE: #2 – Clean more often under dusty conditions or when airborne debris is present. Replace air cleaner
parts when dirty.
8
AIR CLEANER SERVICE
AVOID FIRES!
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WARNING
• Never operate an engine with the air cleaner
assembly or air cleaner cartridge removed!
A properly serviced air cleaner protects internal engine parts from airborne dirt and dust particles. If air
cleaner instructions are not followed, particles that
should be collected in the air cleaner will pass into
the engine. These particles are abrasive and will
cause the piston rings and cylinder bore to wear
quickly. As the rings and bore wear, the abrasive particles enter the crankcase and contaminate the oil,
forming an abrasive mixture that will wear internal
parts.
Examine the air cleaner on every engine brought in
for a check up or repair. If the air cleaner shows signs
of neglect, show it to the customer before cleaning.
Instruct the customer on proper care to assure long
engine life.
NOTE: Replace worn or damaged air cleaner gas-
kets and mounting gaskets to prevent dirt
and dust from entering engine through improper sealing. Replace air cleaner mounting bracket if bent.
Fig. 1
Remove and service foam pre-cleaner, if equipped,
every 25 hours or every season, whichever occurs
first. Service cartridge every 100 hours or every season, whichever occurs first.
NOTE: Service air cleaner more often under dusty
conditions.
Round Air Cleaner
1. Remove cover (1), knob (2), plate (3), and air
cleaner cartridge (4) with pre-cleaner (5), Fig. 1
or Fig. 2.
Fig. 2
2. Remove foam pre-cleaner from cartridge.
3. Wash pre-cleaner in liquid detergent and water.
4. Squeeze dry in a clean cloth. Set aside.
5. Inspect cartridge. Replace if damaged or dirty.
9
1
CAUTION: DO NOT use petroleum solvents to
clean paper cartridge.
DO NOT oil paper cartridge.
DO NOT use pressurized air to clean or dry paper
cartridge.
6. Reinstall pre-cleaner over cartridge.
7. Install cartridge to air cleaner.
8. Install plate, knob and air cleaner cover.
Square Air Cleaner
1. Remove knob(s) (2) and cover assembly (1),
Fig. 3.
Cyclonic Air Cleaner
NOTE: The debris valve automatically discharges
dust and debris. There should be minimal
debris for removal.
1. Remove debris from the air cleaner by
squeezing the ends of the debris valve (5),
Fig. 4.
Fig. 3
2. Remove cartridge (4) and pre-cleaner (5) from
cover.
3. Wash pre-cleaner in liquid detergent and water.
4. Squeeze dry in a clean cloth. Set aside.
5. Inspect cartridge. Replace if damaged or dirty.
CAUTION: DO NOT use petroleum solvents to
clean paper cartridge.
DO NOT oil paper cartridge.
DO NOT use pressurized air to clean or dry paper
cartridge.
6. Install pre-cleaner in cover with foam toward
cover. (Nylon screen toward paper element.)
Fig. 4
2. Remove the cover (4) from the air cleaner
housing (1).
3. Remove the primary filter (3) and inspect.
Replace the filter if damaged, or dirty.
CAUTION: DO NOT clean or oil these filters.
DO NOT use pressurized air to clean or dry filters.
REPLACE filters if damaged or dirty
4. Inspect the safety filter (2).
NOTE: DO NOT remove the safety filter (2) as part
of the inspection.
If it is necessary to remove the safety filter,
Fig. 5, be sure all debris is removed from the
air cleaner housing before removal.
Replace the safety filter with every third
replacement of the primary filter, or if
damaged or dirty.
7. Install paper cartridge in cover with tabs on
cartridge (3) in slots of cover, Fig. 3.
8. Reinstall cover assembly on air cleaner body.
10
5. Reinstall filter(s).
6. Reinstall air cleaner cover.
1LOCKED FOR PRINTING – SELECT SECT. NEEDED >
CARBURETOR ADJUSTMENTS
Models 290000 – 350000
The Vanguard OHV twin cylinder engine carbure-
tor fuel mixture adjustment procedure is unique. Perform adjustments exactly in the sequence shown.
NOTE: If engine is equipped with Performance
Control electronic governor see separate
adjustment procedure.
Initial Adjustment
Fig. 5
ARMATURE AIR GAP ADJUSTMENT
1. Loosen screws holding armature in place. Slide
armature away from flywheel and tighten one of
the screws.
2. Rotate flywheel until magnet is under armature
laminations.
3. Place thickness gauge (1) between magnet and
armature laminations, Fig. 6.
• All EXCEPT Models 540000, 610000 – Use
0.008” – 0.012” (0.20 – 0.30 mm) gauge.
• Models 540000, 610000 – Use 0.005 – 0.007”
(0.13 – 0.18 mm) gauge.
1. Turn idle mixture screw (1), Fig. 7, CLOCKWISE
until it just seats. DO NOT FORCE.
2. Turn valve COUNTERCLOCKWISE 1-1/4
turns.
This setting will permit engine to start. Final adjustment will be made with engine running.
NOTE: Parts removed for clarity.
Fig. 6
4. Loosen screw on the armature. Allow armature
to be pulled against the gauge by the flywheel
magnet. Tighten both armature screws to 25 in.
lbs. (3 Nm).
5. Rotate flywheel to remove gauge.
6. Repeat procedure for the other armature.
Fig. 7
If engine is equipped with a secondary governor
spring, Fig. 8, check governor lever adjustment
procedure before starting engine.
(1) Primary Governor Spring
(2) Loop (faces UP)
(3) Secondary Governor Spring
(4) Loop Over Tab
(5) #2 Hole (Generators)
(6) #1 Hole (Remote Control)
11
1
Ì
Fig. 8
Final Adjustment
All carburetor adjustments performed with the engine running must be made with the air cleaner
installed.
• Tools Required, Fig. 9:
Tachometer #19200 or #19389
Fig. 10
4. Turn idle mixture screw slowly CLOCKWISE (1)
until engine speed just starts to slow (LEAN
mixture), Fig. 11.
Tang Bender #19352
1. Start engine. Run for approximately 5 minutes to
allow engine to warm up.
2. Move control lever on equipment to SLOW
position.
1938919200
19352
Fig. 9
3. Hold throttle lever (2) against idle speed screw
(1), Fig. 10. Temporarily adjust idle to RPM
shown below.
Fig. 11
5. Then turn idle mixture screw COUNTERCLOCKWISE (3) until engine speed just starts to
slow (RICH mixture).
6. Turn screw to mid point (2) between RICH and
LEAN.
7. Hold throttle lever against idle speed adjustment
screw and re-adjust idle to RPM shown below:
a. 1200 RPM – Governed Idle Spring #805453
(RED).
b. 900 RPM – Governed Idle Spring #805454
(WHITE).
8. Release throttle lever. Note RPM.
9. If necessary bend governed idle tang (5) with
Tang Bender #19352 (4), Fig. 12, to obtain RPM
shown:
a. 1400 RPM – Governed Idle Spring #805453
(RED).
b. 1100 RPM – Governed Idle Spring #805454
(WHITE).
12
a. 1750 RPM – Governed Idle Spring #805453
(RED).
b. 1100 RPM – Governed Idle Spring #805454
(WHITE).
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10. If the carburetor is equipped with an idle mixture
limiter cap install it at this time.
a. Position limiter cap (7) so that stop(s) on
limiter cap are at mid point between stop(s)
on carburetor body, Fig. 13.
Fig. 12
Fig. 14
Performance Control Engines
NOTE: All carburetor adjustments with engine
running must be made with the air cleaner
correctly installed.
1. Start engine and run it for approximately 5
minutes to allow engine to reach operating
temperature.
2. Activate idle down device, or ground BLUE wire
(1) from control module using a jumper wire (2),
Fig. 15.
3. Temporarily adjust idle speed to 1400 RPM.
Fig. 13
b. Press limiter into position using Knock Out
Pin, #19135 (6) as shown.
11. With equipment control lever in SLOW position
and engine running at governed idle, use Tang
Bender, #19352 (9), to bend throttle restrictor
tang (8) so that tang just contacts governor lever
(10), Fig. 14.
12. Move equipment control to FAST position.
Engine should accelerate smoothly.
Re-adjust idle mixture valve 1/8 turn richer if
necessary.
Fig. 15
4. Turn idle mixture screw slowly CLOCKWISE (3)
until engine speed just starts to slow (LEAN
mixture), Fig. 16.
5. Then turn idle mixture valve COUNTERCLOCKWISE (5) until engine speed just starts to slow
(RICH mixture).
6. Turn valve to mid point (4) between RICH and
LEAN.
7. Re-adjust idle speed to 1750 RPM.
13
1
NOTE: Idle speed may vary according to OEM
specifications.
Fig. 16
8. Deactivate idle-down device, or remove jumper
wire. Engine should accelerate smoothly to top
governed speed. Re-adjust idle mixture screw
1/8 turn richer if necessary.
9. If the carburetor is equipped with an idle mixture
limiter cap, install it at this time.
a. Position limiter cap (7) so that stop on limiter
cap is at mid point between stops on
carburetor body, Fig. 17.
Fig. 18
2. Then turn screw COUNTERCLOCKWISE 3/4
turn.
Fig. 17
b. Press limiter into position using Knock Out
Pin #19135 (6).
Models 351400, 380400, 351700 and 380700
The OHV twin cylinder engine carburetor fuel
mixture adjustment procedure is unique. Perform
adjustments exactly in the sequence shown.
Horizontal crankshaft engines (1) and vertical
crankshaft engines (2) are shown in Fig. 18.
Initial Adjustment
3. Repeat for #2 cylinder.
This setting will permit engine to start. Final adjustment will be made with engine running.
Final Adjustment
Carburetor adjustments performed with engine running must be made with the air cleaner correctly
installed.
NOTE: Idle mixture adjustment MUST be per-
formed with the engine running at 1200
RPM.
Tools Required:
• Tachometer #19200 or #19389
• Tang Bender #19352
1. Start engine and run it for approximately 5
minutes to allow engine to reach operating
temperature.
2. Move equipment control lever to SLOW
position.
1. Turn idle mixture screw for #1 cylinder CLOCKWISE until it just seats. DO NOT FORCE,
Fig. 18.
14
3. Hold throttle lever (1) against idle speed screw
(2), Fig. 19. Temporarily adjust idle to 1200
RPM.
1LOCKED FOR PRINTING – SELECT SECT. NEEDED >
4. While holding throttle lever, SLOWLY turn idle
mixture screw for #1 cylinder CLOCKWISE until
engine speed just starts to slow (LEAN mixture).
Fig. 19
5. Then turn idle mixture screw (3) COUNTER-
CLOCKWISE 3/8 turn, Fig. 20.
NOTE: It may be necessary to re-adjust idle speed
to 1200 RPM before proceeding.
a. 1750 RPM – Governed Idle Spring #805453
(RED).
b. 1100 RPM – Governed Idle Spring #805454
(WHITE).
NOTE: Parts removed for clarity.
Fig. 21
10. If carburetor is equipped with idle mixture limiter
caps, install at this time.
6. Adjust idle mixture screw for #2 cylinder as
described in steps 4 and 5.
7. If necessary, re-adjust idle speed screw to RPM
shown below.
a. 1200 RPM – Governed Idle Spring #805453
(RED).
b. 900 RPM – Governed Idle Spring #805454
(WHITE).
8. Release throttle lever. Note RPM.
Fig. 20
9. If necessary, use Tang Bender #19352 (6),
Fig. 21. Bend governed idle tang LEFT to
INCREASE (4), right to DECREASE (5) engine
speed to obtain RPM shown:
a. Position limiter cap (8) so that stop on limiter
cap is at mid point between stops on carburetor body. Press limiter into position using
Knock Out Pin #19135 (7) as shown in,
Fig. 22.
b. Repeat for other idle mixture valve.
11. With equipment control lever in SLOW position
and engine running at governed idle, use Tang
Bender #19352 (10), to bend throttle restrictor
tang (9) so that it just contacts governor lever
(11), Fig. 23.
12. Move equipment control to FAST position.
Engine should accelerate smoothly. Re-adjust
idle mixture valve 1/8 turn richer if necessary.
Fig. 22
15
1
Remove deposits from combustion chamber and
around valves using a wire brush or scraper. With
piston at Top Dead Center (TDC), remove
combustion chamber deposits from top of piston.
Use care to prevent combustion chamber deposits
from entering push rod or oil return cavity in cylinder.
Take care not to damage cylinder, top of piston,
cylinder head and cylinder head gasket surfaces.
11
Fig. 23
Choke Control Adjustment
NOTE: Be sure choke control wire is installed in #2
hole (2) in choke lever, Fig. 24.
Fig. 24
1. Place choke control lever on equipment in
CHOKE position.
NOTE: Remove only the combustion chamber de-
posits. It is not necessary to remove the discoloration marks on the piston, valves and
cylinder head. These marks are normal and
will not affect engine operation.
Remove the loose deposits from around the top ring
land area using compressed air or a soft bristle
brush.
Cooling System Cleaning
Grass particles, chaff or dirt can clog the air cooling
system, especially after prolonged service in cutting
dry grass or very dirty air. Operating with a clogged
cooling system can cause overheating and engine
damage. Cleaning the cooling system should be a
regular maintenance operation, performed yearly or
every 100 hours, whichever comes first.
All Except Models 540000, 610000
Fig. 25 shows the blower housing removed and
areas to be cleaned (1) on the Vanguard engine.
2. Loosen control casing clamp screw (4).
3. Move control casing and wire (3) until choke is
completely closed (1).
4. Tighten casing clamp screw.
Combustion Chamber Deposits
Combustion chamber deposits should be removed
every 500 hours or whenever cylinder heads are
removed.
WARNING
AVOID EYE INJURY!
• Wear eye protection whenever using
compressed air to clean parts.
16
Fig. 25
1LOCKED FOR PRINTING – SELECT SECT. NEEDED >
Ì
Models 540000, 610000
1. Use a coin or screwdriver to twist the Easy Clean
Access panel fasteners (1), Fig. 26
COUNTERCLOCKWISE until a CLICK is heard
(approx. 3/4 turn).
2. Remove the panel (2).
Fig. 26
3. Blow compressed air from the PTO side to clean
the cooling fins (3), Fig. 27 around each cylinder
and to back flush the cooling system.
Fig. 28
Fig. 29
Fig. 27
4. Insert the access panel tab into the blower housing slot. Be certain the access panel is correctly
engaged to the blower housing. Push the panel
completely into the housing. Twist each fastener
CLOCKWISE until it “CLICKS”, approx. 3/4 turn.
CAUTION: DO NOT run the engine unless the
Easy Clean Access panel is correctly installed.
Crankcase Oil
Change Oil and Filter
Drain oil while the engine is still warm. See Fig. 28
for approximate drain plug locations on vertical
crankshaft engines; Fig. 29 for horizontal crankshaft
engines.
1. Remove oil drain plug (1). Drain oil into
approved container.
2. Remove dipstick.
3. Replace oil filter (2) every 100 hours. Before
installing new filter, lightly oil filter gasket with
new engine oil.
4. Screw filter on CLOCKWISE (arrow) by hand
until gasket contacts filter adapter. Hand tighten
an additional 1/2 - 3/4 turn.
5. Replace drain plug.
6. Refill crankcase slowly with new oil of proper
service classification and viscosity grade. Refill
to FULL mark on dipstick.
CAUTION: DO NOT OVERFILL THE ENGINE
WITH OIL!
17
1
The crankcase capacity of Vanguard V-Twin
engines is approximately:
• All (except Model 540000) – 48 oz. (1.4
liters) with filter
• Models 540000, 610000 – 79 oz. (2.3
liters) with filter
• Models 540000, 610000 – 71 oz. (2.1
liters) without filter
NOTE: When checking oil level, screw the dipstick
all the way in for accurate readings.
7. Start engine. Run at IDLE for 30 seconds and
stop engine. Recheck oil level and add if
required. Restart engine and check for oil leaks.
Governor Adjustments
CAUTION
AVOID INJURY! Complete the
governor static adjustment BEFORE
starting or running engine.
CAUTION:
2. Use a screwdriver (2) to rotate governor shaft
COUNTERCLOCKWISE as far it will go. Torque
governor nut to 70 in. lbs. (8 Nm).
3. Install throttle and choke control cables and
check for proper operation.
Dynamic Governor Adjustment
NOTE: Carburetor mixture adjustments must be
• Tools Required, Fig. 31:
Tachometer #19200 (1) or #19389 (3)
Tang bender #19352 (2)
Do not bend governor link or distort
governor lever.
made before adjusting governed idle,
throttle restrictor and top no-load RPM.
• Incorrect adjustment could result in engine
overspeeding, causing engine damage,
property damage or personal injury.
Static Governor Adjustment
(Before Running Engine)
1. Loosen governor lever nut. Push on governor
lever (1) until throttle is wide open, Fig. 30.
Fig. 31
Manual Friction and Remote Speed Controls
Governor spring is installed in #1 hole (3) in governor
lever, Fig. 32.
Start and run engine for approximately 5 minutes to
allow engine to warm up.
1. Move control lever to SLOW position.
2. Use tool #19352 (1) to bend governed idle tang
(2) to obtain RPM shown:
Fig. 30
18
a. 1750 RPM – Governed Idle Spring #805453
(RED).
b. 1100 RPM – Governed Idle Spring #805454
(WHITE).
1LOCKED FOR PRINTING – SELECT SECT. NEEDED >
Fixed Speed Adjustable – Except Generators
Governor spring is installed in #1 hole in governor
lever (3), Fig. 35.
Start and run engine for approximately 5 minutes to
allow engine to warm up.
1. Turn fixed speed adjustable control nut counterclockwise until control swivel contacts slow
speed stop.
3. With equipment control lever in SLOW position
and engine running at governed idle RPM, use
Tang Bender #19352 (1), to bend throttle
restrictor tang (4) so that it just contacts
governor lever (5), Fig. 33.
Fig. 32
Fig. 33
4. Refer to Service Engine Sales Microfiche,
MS-6225 or the Service Engine Sales Manual,
MS-4052, for Top No-Load RPM by engine
Model and Type Number.
5. Move control throttle lever to FAST position and
check engine RPM.
6. Use Tool #19352 (1) to bend tang (6) UP (7) to
increase and DOWN (8) to decrease engine
speed, to obtain desired Top No-Load RPM,
Fig. 34.
NOTE: Air cleaner removed for clarity.
2. Use Tool #19352 (1) to bend governed idle tang
(2) to obtain RPM shown:
a. 1750 RPM – Governed Idle Spring #805453
(RED).
b. 1100 RPM – Governed Idle Spring #805454
(WHITE).
Fig. 35
3. Use Tool #19352 (1) to bend throttle restrictor
tang (4) so that it just contacts governor lever (5),
Fig. 36.
Fig. 34
Fig. 36
NOTE: Be sure the governor spring is installed in #1
hole in governor lever (9), Fig. 37.
4. Refer to Service Engine Sales Microfiche,
MS-6225 or the Service Engine Sales Manual,
MS-4052, for Top No-Load RPM by engine
Model and Type Number.
19
1
5. Turn fixed speed adjustable control nut (6)
clockwise (8) to increase or counter-clockwise
(7) to decrease engine speed until desired Top
No-Load RPM is obtained, Fig. 37.
Fig. 37
Fixed Speed Adjustable – Generators
No governed idle spring is used with this system. No
throttle restrictor adjustment is necessary. The
primary governor spring (1) is installed in #2 hole on
governor lever (5). A secondary governor spring (3)
is installed with loop (4) over the governor lever tab
(4), and the rear loop facing (2) UP as shown in
Fig. 38.
Adjust Secondary Governor Spring
1. Disengage the adjustable fixed speed control
nut (Inset, Fig. 40).
2. Loosen and remove fixed speed adjustable
control nut, spring and retainer.
3. Rotate governor control swivel (1) counterclockwise to end of travel, Fig. 39.
4. Install Adjustment Gauge #19385 (3), with notch
over end of governor lever and flat end of tool
against governor control bracket as shown in
Fig. 39.
5. Hold gauge in position and bend tab (5) with Tang
Bender #19352 (4) so that all slack is removed
from secondary governor spring (2) between its
two anchor points, Fig. 39. DO NOT STRETCH
SPRING.
6. Remove adjustment gauge.
NOTE: Secondary governor spring must be
adjusted BEFORE the engine is started.
Perform adjustment in the sequence
shown.
Fig. 38
Fig. 39
Start engine. Run for approximately 5 minutes to
allow engine to warm up.
7. With engine running, pull control rod (7) out until
swivel is against stop. Hold in this position,
Fig. 40.
8. Use tang bender (4) to bend tang (6). Adjust to
Top No-Load RPM for the type of generator
listed in Table 1.
9. Re-install control nut, spring and retainer. Turn
nut clockwise until threads on control rod are
visible from end of nut, inset Fig. 40.
20
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TABLE NO. 1
Generator
Type
3600 RPM
60 Cycle
3000 RPM
50 Cycle
Top No-Load
RPM
4250 RPM 3750 RPM
3600 RPM 3150 RPM
Regulated
No-Load RPM
Fig. 40
10. Engage fixed speed adjustable control nut (8)
and adjust to Regulated No-Load RPM for the
type of generator listed in Table 1, Fig. 41.
a. Turn nut CLOCKWISE (10) to increase
speed.
b. Turn nut COUNTERCLOCKWISE (9) to
decrease speed.
NOTE: Final adjustment should be made with
generator loaded to rated capacity or to
manufacturer’s specifications.
Adjust Secondary Governor Spring
1. Move equipment control to SLOW position.
2. Install Adjustment Gauge #19385 (4), with notch
over end of governor lever and flat end of tool
against governor control bracket as shown in
Fig. 42.
3. Hold gauge in position and bend tab (2) with Tang
Bender #19532 (1), so that all slack is removed
from secondary governor spring (5) between its
two anchor points, Fig. 42. DO NOT STRETCH
SPRING.
4. Remove adjustment gauge.
Fig. 41
Remote Speed Control Engines Equipped With
Secondary Governor Spring
Some Vanguard OHV V-Twin engines with remote
speed control are equipped with a secondary governor spring (5). The primary governor spring is
installed in #1 hole (3) on governor lever, Fig. 42.
NOTE: The secondary governor spring must be
adjusted BEFORE the engine is started.
Perform the adjustment in the sequence
shown.
Start engine. Run for approximately 5 minutes to
allow engine to warm up.
5. Move control lever to SLOW position.
6. Use tang bender (1) to bend governed idle tang
(6) to obtain RPM shown, Fig. 43:
a. 1750 RPM – Governed Idle Spring #805453
(RED).
b. 1100 RPM – Governed Idle Spring #805454
(WHITE).
NOTE: Engine Model 303447 Type 0411-01 – Set
governed idle to 1350 RPM 50 RPM.
Fig. 42
21
1
7. With equipment control lever in SLOW position
and engine running at governed idle RPM, use
Tang Bender #19352 (1), and bend throttle
restrictor tang (7) so that tang just contacts
governor lever (8), Fig. 44.
Fig. 43
Fig. 45
Oil Cooler
Some engines are equipped with an oil cooler,
Fig. 46. The oil cooler is mounted on the blower
housing. Filtered oil is routed through the oil cooler
through two oil lines from a special oil filter adapter.
Forced air from the flywheel fan flows through the oil
cooler fins dissipating heat from the engine oil.
The oil cooler fins should be cleaned every 100
hours, checked periodically for debris, and cleaned
with compressed air or a soft bristle brush.
Fig. 44
8. Refer to Service Engine Sales Microfiche,
MS-6225 or the Service Engine Sales Manual,
MS-4052, for Top No-Load RPM by engine
Model and Type Number.
9. Move control throttle lever to FAST position and
check engine RPM.
10. Bend tang (8) with Tool #19352 (1) to obtain desired top no-load RPM, Fig. 45.
NOTE: Engine Model 303447 Type 0411-01 – Set
Top No-Load Speed to 2900 RPM 50
RPM.
22
Fig. 46
Spark Plugs
Replace spark plugs every 100 hours of operation or
every season, whichever occurs first. Replace spark
plugs if electrodes are burned away, or if the
porcelain is cracked.
NOTE: Do not blast-clean spark plugs. Spark plugs
should be cleaned by scraping or hand wire
brushing and washing in a commercial
solvent.
Use a wire gauge (1) to set spark plug gap, Fig. 47.
Torque spark plugs to 180 in. lbs. (20 Nm).
1LOCKED FOR PRINTING – SELECT SECT. NEEDED >
Fig. 47
All Except Models 540000, 610000
Resistor spark plugs recommended by Briggs &
Stratton:
• B&S #491055 (Champion RC12YC) or
• B&S #496018 (Champion RC14YC)
Gap to 0.030” (0.76 mm).
FAST
SLOW
Fig. 48
Valve Clearance Adjustment
1. Set No. 1 cylinder at 1/4” (6 mm) past TDC,
compression stroke.
Models 540000, 610000
Resistor spark plug recommended by Briggs &
Stratton:
• B&S #692051
Gap to 0.020” (0.51 mm).
Speed Control Wire Adjustment
NOTE: Manual friction and remote control
adjustment procedure is identical.
1. Loosen control casing clamp screw (1) at
governor control bracket, Fig. 48.
2. Move speed control lever to FAST position (in-
set, Fig. 48).
3. Move control casing and wire until governor
control swivel is at end of travel.
2. Use a feeler gauge (1) to measure the valve
clearance. Valve clearance should be 0.005”
(0.13 mm) for the intake and exhaust valve.
NOTE: Measure valve clearance with the engine
COLD.
3. If the valve clearance requires adjustment,
loosen the lock nut (2) with a wrench (4). Use a
hex wrench (5) to turn the adjusting screw (3) to
adjust the valves, Fig. 49.
4. With the valve clearance correctly adjusted,
hold the adjusting screw. Torque the lock nut to
70 in. lbs. (8 Nm).
5. Repeat for No. 2 cylinder.
4. Tighten casing clamp screw.
Fig. 49
23
1
TUNE-UP PROCEDURE
A “Tune-Up,” see the steps listed below, would normally be performed on relatively new engines brought in for
minor difficulties. By performing these steps you will either be sure that the engine is functioning properly or will
know what major repairs should be made. The steps are also covered in the Overhaul Procedure and will normally
be performed as a part of the complete overhaul.
1. Disconnect and ground spark plug wires.
2. Remove air cleaner cartridge, check for proper
servicing. Check gaskets, pre-cleaner and
cartridge for damage.
3. Check oil level. Drain oil. Remove oil filter.
4. Remove blower housing, inspect rewind
assembly when equipped.
touch flywheel. Check ground wire and stop
switch connections.
10. Remove cylinder heads. Remove carbon.
Check head gaskets. Inspect valves for seating.
11. Install cylinder heads and new gaskets. Tighten
to specified torque. Adjust valve clearance. Set
spark plug gaps.
5. Clean cooling fins and entire engine.
6. Check governor, linkage and springs for
damage and wear. Check governor adjustment.
7. Remove intake manifold and carburetor.
Disassemble carburetor. Wash in solvent and
inspect for wear or damage. Replace gaskets
and parts as necessary. Reinstall carburetor on
manifold. Set initial adjustment.
8. Replace spark plugs. Remove flywheel. Check
flywheel key. Check for oil seal leakage on both
flywheel and PTO sides.
9. Check coils. Inspect all wires for breaks and/or
damaged insulation. Be sure ground wires do not
12. Reinstall intake manifold using new gaskets.
13. Reinstall blower housing.
14. Install new oil filter. Replace oil and fuel.
15. Adjust equipment control and cables, if used, for
correct operation.
16. Service air cleaner pre-cleaner and cartridge, or
replace.
17. Check muffler for restrictions or damage.
18. Start engine and bring up to operating
temperature. Then, adjust carburetor mixture
and engine top speed.
OVERHAUL PROCEDURE
The following Overhaul Procedure is intended to help you to establish a systematic method of repairing Briggs
& Stratton OHV engines. These steps may be performed in a different order but best efficiency is obtained when
the repairs are performed in the same sequence every time. The exact procedure will vary according to the engine
model being repaired. Be careful to locate the instructions covering the specific model being repaired.
Disassemble
1. Drain oil. Remove oil filter.
2. Remove spark plugs.
3. Air cleaner assembly (if equipped).
Fuel tank and bracket assembly (if equipped).
Fuel pump and bracket (if equipped).
4. Rotating screen (if equipped). Blower housing.
5. Rewind starter (if equipped).
6. Exhaust manifold, muffler(s).
7. Intake manifold and carburetor.
8. Check throttle shaft and bushings for wear.
9. Disassemble carburetor.
10. Check armature air gap. Remove armatures.
11. Flywheel.
12. Electric starter.
13. Breather. Valve covers and valley cover.
14. Governor control bracket.
15. Check valve clearances.
16. Cylinder shields, rocker arms, push rods,
cylinder heads.
17. Valves, springs and seals. Inspect valve guides
and seats.
18. Check crankshaft end play. Remove burrs from
crankshaft extension.
19. Crankcase cover. Inspect bearings. Remove oil
seal.
20. Cam gear and tappets. Inspect governor.
21. Connecting rods and pistons.
22. Inspect crankshaft.
24
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23. Cylinder – check cylinder bores and bearings.
Remove oil seal.
24. Disassemble and check connecting rods,
pistons, piston pins and rings.
25. Disassemble and inspect oil pump.
Inspection and Repairs
1. Clean parts.
2. Resize cylinder bore as required.
3. Replace main bearing.
4. Replace all oil seals.
5. Replace valve guides.
6. Reface and lap valves and seats.
7. Replace armatures.
8. Repair carburetor.
9. Replace rewind starter spring and rope (if
equipped)
Reassemble
1. Crankshaft.
2. Pistons, piston pins, rings and connecting rods.
3. Tappets, cam gear.
4. Mechanical governor.
5. Oil pump.
6. Crankcase cover – check end play. Replace oil
seal.
7. Electric starter.
8. Flywheel and starter pulley (if equipped).
9. Armatures – adjust air gap.
10. Check spark.
11. Valves, seals, springs and retainers.
12. Cylinder heads, push rods, rocker arms and
cylinder shields.
13. Adjust valve clearance.
14. Valve covers, breather and valley cover.
15. Linkage and governor controls.
16. Carburetor and intake manifold.
17. Check and adjust mechanical governor.
18. Blower housing.
19. Fuel pump and bracket (if equipped).
Fuel tank and bracket (if equipped).
20. Clean and assemble air cleaner.
21. Exhaust manifold, mufflers.
22. Install new spark plugs.
23. Replace oil filter. Fill crankcase with oil. Fill with
gas. Start engine.
24. Adjust carburetor.
25. Adjust governor controls to obtain correct
engine speed (remote controls).
26. Re-torque cylinder head screws.
27. Spray paint engine and apply decals.
25
1
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Section 2
Troubleshooting
Page
ELECTRICAL SYSTEMS 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alternators 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alternator System Diagnosis 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Charging System Identification 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flywheel Magnet Identification 34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Equipment Used to Test Alternators 34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Testing Alternator Output 35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC Alternator 35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Alternator 36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dual Circuit Alternator 37. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tri-Circuit Alternator 38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 & 9 Amp Regulated Alternator 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 & 16 Amp Alternator 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20 Amp Regulated Alternator 43. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Powerlink System 45. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Anti-Afterfire Solenoid 47. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Testing Battery 48. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Testing Engine Wiring Harness 50. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Pressure 53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Panel Kit with Key Switch and Solenoid 53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starter Motor 56. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conditions Affecting Starter Motor Performance 56. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting 56. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Testing 56. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Solenoid Test 57. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performance ControlE Electronic Governor 58. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wiring Diagram 58. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Governor Test 59. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing Actuator 59. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EQUIPMENT PROBLEMS AFFECTING ENGINE OPERATION 64. . . . . . . . . . . . . . . . . . . . . . . . . . .
GASEOUS-FUELED ENGINES 61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Guide 61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Carburetor Adjustment 63. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LPG-Only Operation 63. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SYSTEMATIC CHECK 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ignition 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Carburetion 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Compression 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27
2
Most complaints concerning engine operation can be
classified as one or more of the following:
1. Will not start
2. Hard starting
3. Lack of power
4. Runs rough
5. Vibration
6. Overheating
7. High oil consumption
NOTE: What appears to be an engine problem may
actually be the fault of the powered
equipment. If equipment is suspect, see
Equipment Affecting Engine Operation.
SYSTEMATIC CHECK
A systematic check of the engine can be performed
in minutes, and is an accurate method of
determining the source of the problem. The basic
procedure is the same for all engine models.
Variations, by model, will be shown under the subject
heading. If the engine will not start and the cause is
not apparent, perform a systematic check in the
following order:
1. Ignition
2. Carburetion
Fig. 1
If there is NO SPARK look for –
1. Improperly operating equipment interlock
system
2. Shorted equipment stop switch wire
3. Two closed diodes in ground wire harness
(current style) or ground terminal (early style)
4. Incorrect armature air gap
5. Armature failure
3. Compression
Ignition
Test Using Electric Starter
NOTE: MagnetronR ignition systems require a
minimum of 350 RPM to produce spark.
WARNING
AVOID ELECTRICAL SHOCK!
• A partially sheared flywheel key will affect
ignition timing and engine performance.
• Spark can still occur with a sheared flywheel
key. A severe shock or kickback hazard may
exist.
With spark plugs installed, attach Ignition Tester
#19368 (1) to each spark plug lead (2). Ground the
other end of the tester as shown, Fig. 1. Spin the flywheel rapidly with engine starter. If spark jumps the
tester gap the ignition system is working correctly.
Test With Engine Running
If the engine runs, but misses under load, test the
ignition by installing an Ignition Tester #19368 (2)
between the spark plug lead (1) and each spark plug
(3), Fig. 2. A spark miss will be readily apparent
when the engine is running. If the spark appears
good in the tester but the engine misses, check for
a fouled spark plug.
Fig. 2
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Fouled Plug or Dead Cylinder
To test for a fouled spark plug or a non-functioning
cylinder, attach Ignition Tester #19368 (2) between
the spark plug lead (1) and each spark plug (4). With
engine running at top no-load speed, use a
screwdriver (3) with an insulated handle to ground
one spark plug by contacting the alligator clip on the
ignition tester to a good ground on the engine, Fig.
3. The engine should continue to run on the other
cylinder. Repeat this test with the other cylinder. If
the engine dies when performing this test, the
cylinder that is NOT grounded is not functioning
and/or the spark plug is fouled. Install a new spark
plug and re-check. If miss continues see the
following procedures.
If plugs are dry, look for –
1. Leaking carburetor mounting gaskets
2. Gummy or dirty carburetor, fuel line or tank
3. Float needle valve stuck shut
4. Inoperative fuel pump
5. Inoperative anti-afterfire solenoid
To determine if fuel is getting to the combustion
chamber through the carburetor, remove either
spark plug and pour a small quantity of gasoline
through the spark plug hole. Replace the spark plug.
If the engine fires a few times and then stops, look for
the same conditions as for a dry plug.
Compression
Compression Test
Briggs & Stratton does not publish compression
pressures, as it is difficult to obtain an accurate
reading without special equipment. An assessment
of the engine’s compression can be made as follows:
Fig. 3
Carburetion
NOTE: Gaseous fuel engines use carburetors that
must be serviced by a certified gaseous fuel
installer or by a certified dealer for the equipment powered.
Before performing a carburetion check, be sure the
fuel tank has an ample supply of fresh, clean gasoline. Be sure that the shutoff valve, if equipped, is
open and fuel flows freely through the fuel line before starting engine. Inspect and adjust the idle
needle valve. Make sure the choke closes completely. If engine will not start, remove and inspect
the spark plugs.
If plugs are wet, look for –
1. Overchoking
Remove both spark plugs and insert a compression
gauge into either cylinder (one cylinder at a time).
Turn engine over with engine starter until there is no
further increase in gauge pressure reading. Record
this reading. Repeat procedure on other cylinder and
record that reading. Divide the difference between the
cylinders by the compression pressure of the higher
of the two cylinders. A difference over 25% between
the cylinders indicates a loss of compression in the
cylinder with lower pressure. See example below.
Engine #1 Engine #2
Cylinder #1 65 PSI 75 PSI
Cylinder #2 60 PSI 55 PSI
Difference 5 PSI 20 PSI
% Difference 7.7% 26.7%
If compression is poor, look for –
1. Loose cylinder head bolts
2. Blown head gasket
3. Burned valves, burned and/or loose valve seats
4. Insufficient valve clearance
2. Excessively rich fuel mixture
3. Water in fuel
4. Float needle valve stuck open
5. Plugged air cleaner
5. Warped cylinder head
6. Warped valve stems
7. Worn bore and/or rings
8. Broken connecting rods
29
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