Briggs & Stratton Vanguard 430000, Vanguard 580000 User Manual
POST OFFICE BOX 702
MILWAUKEE, WI 53201 USA
©2010 Briggs & Stratton Corporation
BRIGGS&STRATTON
CORPORATION
MS - 0750 - 5/10
www.ThePowerPortal.com (Dealers)
BRIGGSandSTRATTON.COM (consumers)
272147 - Vanguard ™ Single Cylinder OHV Air-Cooled Engines
272144 - Vanguard
™
Twin Cylinder OHV Air-Cooled Engines
275429 - Vanguard
™
Twin Cylinder OHV Liquid-Cooled Engines
MS-1055 - Vanguard
™
3-Cylinder OHV Liquid-Cooled Diesel Engines
Other Briggs & Stratton
Commercial Power Repair Manuals:
Briggs & Stratton
VANGUARD
™
3-CYLINDER OHV LIQUID-COOLED GASOLINE ENGINES
5/10
Vanguard
™ 3-Cylinder OHV
Liquid-Cooled Gasoline Engines
Quality Starts With A
Master Service Technician
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.
This engine repair manual includes the following
engine models:
• MODEL 430000
• MODEL 580000
6
SECTION 1 - Safety
SECTION 2 - Cylinder Heads and Valves
SECTION 3 - Governor, Timing Gears, and Gear Case
SECTION 4 - Flywheel and Rear Seal Retainer
SECTION 5 - Cylinder Block Disassembly
SECTION 6 - Cylinder Block Inspection and Repair
SECTION 7 - Crankshaft, Camshaft, and Bearings
1
2
3
4
5
6
7
SECTION 8 - Pistons, Rings, and Connecting Rods
SECTION 9 - Cylinder Block Assembly
SECTION 10 - Fuel System and Related Components
SECTION 11 - Ignition, Electrical System
SECTION 12 - Lubrication System
SECTION 13 - Cooling System
SECTION 14 - Engine Specifications
8
9
10
11
12
13
14
THISPROPER SERVICE AND REPAIR IS IMPORTANT
TO THE SAFE, ECONOMICAL AND RELIABLE
SECTION 1 - SAFETY AND MAINTENANCE
SAFETY INFORMATION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4
1
1
3
1
1
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 (
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.
DANGER, WARNING, or CAUTION)
WAR NING
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.
Hazard Symbols and Meanings
FIRE EXPLOSION
ELECTRIC
SHOCK
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.
EXPLOSIVE
PRESSURE
ENTANGLEMENT KICKBACK AMPUTATION
TOXIC
FUMES
Battery posts, terminals, and related accessories contain lead and lead compounds - chemicals known to the State of California to cause
cancer and reproductive harm. Wash hands
after handling.
HOT
SURFACE
READ
MANUAL
WARNING
GOGGLES
CHEMICAL
BURNS
4
WARNING
WAR NING
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 authorize the use of these engines on 3-wheel All
Terrain Vehicles (ATVs), motor bikes, fun/recreational go-karts, aircraft products, or vehicles 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 reproductive harm.
WAR NING
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 jurisdictions 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.
Fuel 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 for at
least 2 minutes before removing the fuel
cap.
• Fill fuel tank outdoors or in a well-ventilated 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 frequently for cracks or leaks. Replace if necessary.
• 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.
1
1
5
WAR NING
WAR NING
1
1
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 terminal.
When testing for spark:
• Use approved spark plug tester.
• Do not check for spark with spark plug
removed.
WAR NING
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.
WAR NING
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.
Charging batteries produce hydrogen
gas. Do not store or charge a battery
near an open flame or device that utilizes a pilot light or can create a spark.
WAR NING
Damaged, worn, or loose fuel components 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.
WAR NING
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 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, impellers, pulleys, and sprockets, must be
securely attached.
WAR NING
Rotating parts can contact or entangle
hands, feet, hair, clothing, or accessories.
Traumatic amputation or severe lacerations 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.
6
WAR NING
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.
SECTION 2 - CYLINDER HEAD AND VALVES
REMOVE CYLINDER HEAD - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 9
DISASSEMBLE CYLINDER HEAD - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -10
REMOVE VALVES - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -11
INSPECT CYLINDER HEAD - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -12
DISASSEMBLE ROCKER ARM SHAFT - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -15
ASSEMBLE ROCKER ARM SHAFT- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -16
ASSEMBLE CYLINDER HEAD - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -17
INSTALL CYLINDER HEAD - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -18
ADJUST VALVES- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -20
2
7
2
2
8
Remove Cylinder Head
1. Drain cooling system and disconnect radiator
hoses and bypass hose at water pump.
2. Remove the alternator adjusting bracket
screw (A, Figure 1), V-belt (B), and fan (C),
from the engine.
Figure 1
3. Remove the water pump pulley (A, Figure 2),
water pump (B), and exhaust manifold (C)
from the engine.
2
Figure 3
6. Remove the ignition coil bracket (Figure 4)
and the ignition coils.
NOTE: Remove the exhaust system before
removing exhaust manifold.
Figure 2
4. Remove the fuel line (A, Figure 3) and
governor link and spring (B).
5. Remove the intake manifold (C) and spark
plug wires and spark plugs (D).
Figure 4
7. Remove the valve cover (Figure 5).
Figure 5
8. Set the Number 1 piston at Top Dead Center
(TDC).
9
9. Rotate crankshaft pulley until timing mark on
pulley is aligned with reference point (A,
Figure 6) on timing cover (B).
Disassemble Cylinder Head
1. Loosen cylinder head bolts in the order
shown (Figure 8).
2
Figure 6
• If intake and exhaust valves have
clearance, the Number 1 piston is at TDC
(compression stroke).
• If intake and exhaust valves do not have
clearance, turn crankshaft pulley one
complete revolution. Valves will then have
clearance.
10. Remove rocker arm assembly (A, Figure 7)
and push rods.
11. Remove valve stem caps (B).
NOTE: Mark push rods so that they may be
reassembled in their original position.
2
Figure 8
Figure 7
10
Remove Valves
2. Refer to the following cylinder head
components (Figure 9) when proceeding to
the next part of the disassembly process:
• (A) - Cylinder Head Assembly
• (B) - Cylinder Head Gasket
• (C) - Valve Stem Cap
• (D) - Valve Spring Retainer Locks
• (E) - Valve Spring Retainer
• (F) - Valve Spring
• (G) - Valve
• (H) - Valve Spring Seat
• (J) - Valve Stem Seal
• (K) - Valve Guide
2
Figure 10
NOTE: Place a shop rag or short section of fuel line
under valves inside combustion chamber to hold
valve in place while compressing spring.
4. Use Valve Spring Compressor #19417 to
compress valve springs. Remove the
following parts:
• Valve Spring Retainer Locks
• Valve Spring Retainer
• Valve Spring
• IN and EX valve
• Valve spring seats
5. Remove and discard valve stem seals
(Figure 11).
Figure 9
3. Remove valves (Figure 10).
11
Figure 11
2
Inspect and Repair
Inspect Cylinder Head
NOTE: Be sure all gasket material is removed from
surfaces before checking. Use a gasket scraper if
necessary.
1. Inspect cylinder head for cracks or damage.
2. Use a straight edge (A, Figure 12) to check
cylinder head lower surface for distortion.
• Replace if damaged or if reject gauge
enters valve guide.
2
Figure 14
6. Use Bushing Driver #19367, and press out
valve guide bushing from combustion
chamber (Figure 15).
Figure 12
3. If mounting surfaces are distorted more than
0.1 mm (0.004 in), the cylinder head must be
replaced (Figure 13).
Figure 13
NOTE: It is not recommended that cylinder head
mounting surfaces be resurfaced.
4. Inspect intake and exhaust manifold
mounting surfaces in the same manner. Use
same specifications as cylinder head.
5. Inspect valve guide bushing for damage.
Check valve guide bushings for wear using
Reject Gauge #19382, (A, Figure 14).
Figure 15
7. Check valve guide bushing OD. Then
compare with the following specifications:
• Standard Bushing OD: 11.05 mm (0.435
in.)
• Replacement Bushing OD: 11.08 mm
(0.4362 in.)
8. If bushing OD measurement indicates that a
replacement bushing has already been
installed, the cylinder head must be replaced.
9. Using Bushing Driver #19416, press in new
valve guide bushing until tool bottoms on
cylinder head (Figure 16).
12
2
Figure 16
10. Valve faces may be resurfaced to 30°. Check
valve seat dimensions before resurfacing. (A,
Figure 17) should be 0.05 - 0.06” (1.2 -
1.6mm) and (B) should be at least 0.0312”.
Figure 17
• Lap valves and seats with Valve Lapping
Tool #19258 and Valve Lapping
Compound #94150.
11. Valve seats may be reconditioned using
Valve Seat Cutter #19446.
Figure 18
• Use a 45° (B) cutter to narrow seat from
bottom.
• Use a 15° (C) cutter to narrow seat from
top.
NOTE: If valve seat is loose or cracked, replace
cylinder head.
12. Measure valve stem diameter at specified
distance from end of valve (A, Figure 19).
• Replace IN if less than 0.2343 in. (5.952
mm).
• Replace EX if less than 0.2342 in. (5.948
mm).
NOTE: Inspect valve guide bushings first. If valve
guides are worn, they must be replaced before
refacing valve seats.
If valve seat is wider than 0.05 - 0.06” (1.2 - 1.6mm)
(A, Figure 18), a narrowing cutter should be used to
ensure that contact area of valve seat is centered
on face of valve.
13
Figure 19
13. Inspect valve stem cap for wear (Figure 20).
Replace if cap is worn recessed.
2
2
Figure 20
14. Inspect valve springs for squareness and
free length (Figure 21).
Figure 21
• Replace if out of square more than 0.040
in. (1.0 mm).
• Replace if free length is less than 0.150 in.
(29.2 mm).
14
Disassemble Rocker Arm Shaft
Remove snap rings (A, Figure 22) from ends of
rocker arm shaft (B). Remove set screw (C) from
center rocker arm support (D). Disassemble rocker
arm assembly. Note position of rocker arms (E),
thrust washers (F) and springs (G).
2
Figure 22
1. Check rotor arms and shaft (Figure 23).
Figure 23
2. Check rocker arm bearing. Replace if greater
than 0.395 in. (10.03 mm).
3. Check rocker arm shaft. Replace if less than
0.392 in. (9.957 mm).
4. Check rocker arm studs for stripped threads
and replace if required.
15
Assemble Rocker Arm Shaft
1. Oil all components before assembling.
2. Small grooves in rocker shaft (A) next to oil
holes (B) must face down.
3. Assemble rocker arm (G) components, noting
order of assembly shown in Figure 24.
2
2
Figure 24
4. Note position of three thrust washers (F),
springs (D), snap rings (H)
5. Install set screw (C) in center rocker arm
shaft support (E).
16
Assemble Cylinder Head
Cylinder Head Components (Figure 25)
• (A) - Cylinder Head
• (B) - Cylinder Head Gasket
• (C) - Valve Stem Cap
• (D) - Valve Spring Retainer Locks
• (E) - Valve Spring Retainer
• (F) - Valve Spring
• (G) - Valve
• (H) - Valve Spring Seat
• (J) - Valve Stem Seal
• (K) - Valve Guide
• (L) - Push Rod
• (M) - Rocker Arm Assembly
• (N) - Rocker Arm Stud
2
Figure 25
1. Install new valve stem seals (A, Figure 26).
Oil inner surface and lip of seal before
installing. Press seal on to valve guide
bushing until it bottoms.
Figure 26
2. Install valve spring seats (Figure 27).
17
2
2
Figure 29
Figure 27
NOTE: Lightly coat valve stems with Valve Guide
Lubricant #93963, before installing valves.
3. Install valves.
4. Install valve springs (Figure 28) with Valve
Spring Compressor #19417.
Figure 28
NOTE: After installing valve spring retainer locks,
tap valve spring retainer lightly with a soft hammer
to ensure locks are seated.
Install Cylinder Head
1. Place cylinder head gasket over alignment
dowels on cylinder block (Figure 29).
NOTE: Make sure coolant, oil passages, and head
bolt holes are aligned.
2. Install cylinder head assembly.
3. Lubricate threads of cylinder head bolts with
engine oil.
4. Torque head bolts in 10 ft. lbs. (13.0 Nm)
increments in sequence shown (Figure 30).
Figure 30
NOTE: Current style head bolts are 9 mm diameter.
Early style head bolts are 8 mm diameter. Torque
specifications are different. Torque bolts to values
listed in Section 14 - Engine Specifications.
5. Lubricate push rods with engine oil then
install with recessed end up.
6. Install valve stem caps on valve stems. Install
rocker arm assembly (Figure 31).
18
Figure 33
2
Figure 31
7. Install washers and torque nuts to values
listed in Section 14 - Engine Specifications.
NOTE: Make sure rocker adjustments studs are
seated in recessed end of push rods.
Install ignition coil bracket and ignition coils (Figure
32). Torque screws to values listed in Section 14 Engine Specifications.
8. Install ignition coil bracket and ignition coils
(Figure 32). Torque screws to values listed in
Section 14 - Engine Specifications.
10. Insert governor spring into original hole in
governor lever.
NOTE: Normal spring position is in center hole in
the governor lever (Figure 34).
NOTE: Governor spring must be installed in correct
hole in governor control lever by engine model.
• Model 430400 - Top Hole
• Model 580400 - Bottom Hole
Figure 32
9. Install intake manifold with new gasket. Install
governor link and spring (Figure 33). Torque
screws to values listed in Section 14 - Engine
Specifications.
19
Figure 34
11. Install exhaust manifold with new gasket
(Figure 35). Torque screws to values listed in
Section 14 - Engine Specifications.
2
2
Figure 35
12. Install water pump with new gasket (Figure
36). Torque screws and nuts to values listed
in Section 14 - Engine Specifications.
Figure 36
13. Install water pump pulley (Figure 37). Install
fan (if equipped). Torque screws to values
listed in Section 14 - Engine Specifications.
Figure 38
NOTE: Belt deflection limit is 3/8-1/2 in./22 lb. (10.0-
12.0 mm/10 kg).
Adjust Valves
1. Before adjusting valves, make sure that the
Number 1 cylinder is at Top Dead Center
(TDC) - Compression Stroke (Figure 39).
Figure 39
Figure 37
14. Install V-belt (Figure 38). Install alternator
adjusting bolt. Torque bolt to values listed in
Section 14 - Engine Specifications.
20
2. Adjust valves and check (Figure 40).
• Valve Clearance (cold) IN and EX - 0.007
in. (0.18 mm).
• Torque adjusting screws and jam nuts
to values listed in Section 14 - Engine
Specifications.
Figure 40
3. With Number 1 piston at TDC of compression
stroke, check and adjust valve clearances for
cylinders (Figure 41).
4. Rotate crankshaft one complete turn 360°
clockwise to check and adjust remaining
valves.
5. Install valve cover (Figure 41).Torque cover
nuts to values listed in Section 14 - Engine
Specifications.
2
Figure 41
6. Install spark plugs. Torque spark plugs
to values listed in Section 14 - Engine
Specifications.
21
2
2
22
SECTION 3 - GOVERNOR, TIMING GEARS, AND GEAR CASE
REMOVE TIMING GEAR COVER AND GEARS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -24
INSPECT GEARS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -25
REMOVE GEAR CASE- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -26
DISASSEMBLE GOVERNOR SHAFT ASSEMBLY - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -27
REPLACE TIMING GEAR COVER OIL SEAL - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -27
ASSEMBLE GOVERNOR SHAFT ASSEMBLY - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -27
ASSEMBLE TIMING GEAR CASE AND GEARS- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -28
ADJUST GOVERNOR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -31
TROUBLESHOOTING - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -31
ELECTRONIC GOVERNOR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -32
INSPECT GOVERNOR ACTUATOR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -33
3
REMOVE GOVERNOR ACTUATOR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -33
INSTALL GOVERNOR ACTUATOR - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -33
23
3
TIMING GEARS, GEAR CASE, ELECTRONIC GOVERNOR
3
Remove Timing Gear Cover and Gears
NOTE: Make sure the Number 1 cylinder is at Top
Dead Center (TDC), compression stroke. See
Section 2.
1. Remove V-belt and fan (if equipped).
2. Drain oil from engine.
NOTE: Before removing governor spring, note hole
position of governor spring in governor lever.
3. Remove governor link spring (A, Figure 1)
and governor link from carburetor.
4. Remove governor spring from governor lever
(B).
5. Loosen nut (C) and remove governor lever
from governor shaft.
24
Figure 1
6. Remove oil pan screws and nuts.
7. Remove oil pan and discard gasket.
8. Remove oil pick-up tube (A, Figure 2) and
strainer. Discard gasket.
Figure 2
9. Remove bell housing adapter screw (if
equipped) and install Flywheel Holder
#19418 (A, Figure 3).
3
Figure 4
12. Remove governor gear (A, Figure 5),
governor cup (B), E-ring (C), governor gear
(D), and thrust washer (E).
13. Remove oil pump drive gear (F).
NOTE: Leave tool installed.
10. Remove crankshaft pulley using Tool #19420
(B).
Figure 3
11. Remove trigger (A, Figure 4) and wire.
Remove timing gear cover (B) and discard
timing gear gasket.
Figure 5
14. Check governor gear and oil pump drive gear
for damaged teeth.
Inspect Gears
1. Inspect gear teeth for wear or damage.
2. Check gear back lash between idler gear (A,
Figure 6) and crankshaft gear (B) using a dial
indicator.
• Set tip of indicator on gear tooth, then rock
idler gear back and forth noting indicator
reading.
• Crankshaft must not turn while checking.
25
7. If gears are worn, it is recommended that
they be replaced as a set.
3
Figure 6
3. If back lash exceeds 0.008 in. (0.2 mm)
check idler gear bearing and shaft for wear
(Figure 7).
Reject dimensions for Idler Gear:
• ID - 0.345 in. (34.17 mm)
• OD - 1.335 in. (33.91 mm)
Figure 7
3
Figure 8
Remove Gear Case
1. Remove three screws (A, Figure 9) and
camshaft retainer.
2. Remove remaining five screws (B).
4. If idler gear bearing and shaft are within
specification, replace with new idler gear and
recheck.
5. If back lash exceeds 0.008 in. (0.2 mm) with
NEW idler gear, crankshaft gear is worn.
NOTE: If crankshaft gear is worn the crankshaft
must be replaced.
6. Hold idler gear and check gear backlash
between camshaft timing gear (A, Figure 8)
and idler gear (B) using a dial indicator.
NOTE: Idler gear must not turn while checking.
26
Figure 9
3. Remove timing gear case and discard
gasket.
4. Remove oil pump rotor (Figure 10) from
cylinder block.
Figure 12
3
Figure 10
Disassemble Governor Shaft Assembly
1. Remove cotter pin (A, Figure 11) and washer
(B). Discard cotter pin.
2. Remove screws (C) and governor paddle (D)
using Torx® Driver #19445. Discard screws.
NOTE: Governor paddle screws are Torx® tamper
proof screws.
3. Remove shaft (E) and spacer (F).
4. Remove and discard oil seal (G).
Figure 11
Replace Timing Gear Cover Oil Seal
1. Drive out oil seal.
2. Use Seal Driver #19423 to install new oil seal
(Figure 12).
Assemble Governor Shaft Assembly
1. Install thrust washer (A, Figure 13) on shaft
followed by the governor gear (B), E-ring
(C), and governor cup (D).
Figure 13
NOTE: Lubricate governor shaft with engine oil
before installing.
2. Install new oil seal (A, Figure 14) with seal
lips in.
3. Install governor shaft (B) and spacer (C).
4. Install governor paddle (D) using new screws
(E). Use Torx® Driver #19445. Torque to
values listed in Section 14 - Engine
Specifications.
5. Install washer (F) and new cotter pin (G).
NOTE: Governor shaft must rotate freely.
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