PDF Service Manual Yale A810 (GPGLP030 040AF) EF2 Engine - 544 KB
This service manual is specifically for the EF2 engine used in the Yale A810 series forklifts, including models GP030AF and GLP040AF.
It provides in-depth instructions for maintenance, troubleshooting, and complete overhaul.
Follow step-by-step procedures and specifications to ensure your engine runs smoothly.
An essential resource for any technician working on these Yale models.
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--- Page 1 ---
Sheet 1: General Information
SUPPORT INFORMATION
Your new Yale Industrial Truck is important to you and to your dealer for Yale lift trucks. You measure the return on
the investment in your lift truck through the performance of those lift trucks, the drivers who operate them and the
mechanics who service them safely and efficiently. The following information and programs are made to help fill your
needs:
SERVICE PARTS ORDERING INSTRUCTIONS
How To Order Service Parts
In order to prevent delay, and to have your orders filled correctly, quickly and at the lowest cost, do the following
procedure to order replacement parts.
When Ordering Parts
Your authorized dealer for Yale lift trucks needs the following information:
1. Your Purchase Order number.
2. Complete addresses for sending the invoice and parts.
3. Tell us how you want your parts sent. If we do not get this information, we will send the parts using the
lowest priced method.
4. Correct part numbers and descriptions. Use your parts manual as a reference.
5. Model and serial number of the truck.
SPECIAL TOOLS
Yale makes a variety of special tools for servicing lift trucks. They are available to users who do their own
maintenance. Your dealer for Yale lift trucks is ready to help.
TECHNICAL SERVICE PUBLICATIONS
Technical literature, with detailed information, is available at a nominal fee to assist users to effectively maintain Yale
Industrial Trucks in a safe, useful condition. Parts Manuals with complete replacement parts identification, Operators
Manuals which provide operating procedures and additional copies of this Service Maintenance Manual can be
obtained from your Yale Industrial Truck Dealer.
OPERATOR TRAINING
The Yale "Basic Operator Training' program helps industrial truck users increase their materials handling production
and safety through correct lift truck operation, training and motivation. The Yale program is based upon real life
experience - not theoretical concepts. We developed a "complete' program that is totally self-contained -
incorporating the most modern instructional techniques, including elements of self-stu-dy, audio-visual support (both
video and slides), and classroom study.
DAILY OPERATOR CHECK-OFF LISTS
According to OSHA requirements, lift truck operators must examine their industrial trucks before each shift of
operation. The OPERATOR'S DAILY CHECK LIST can help operators comply with the these OSHA regulations and
give a fast easy inspection system that can be completed efficiently. A sample of the OPERATOR'S DAILY CHECK
LIST is shown on the following page.
SERVICE TRAINING COURSES
Operators and dealer for Yale lift trucks service technicians can improve their technical ability for maintaining and
repairing Yale Industrial Trucks and decrease repair time and cost by taking the Yale Service Training courses.
Different types of mechanical, electric and electronic subjects are available. Courses are available at customer and
Dealer locations in addition to regularly scheduled courses which are held at Yale Corporate Headquarters in
--- Page 3 ---
Sheet 2: Specifications and Maintenance
Figure 2-8. Throttle Arrangement, GP/GLP/GDP 040-065 RF/TF
FOOT DIRECTIONAL CONTROL PEDAL SHOWN
1. PEDALPAD
2. LINK
3. CRANK
4. PEDAL FRAME
5. FORWARD SOLENOID (BLACK WIRE)
6. BATTERY (RED WIRE)
7. REVERSE SOLENOID (YELLOW WIRE)
8. CORRECT HOLES FOR THE LINKAGE
TROUBLESHOOTING
PROBLEM POSSIBLE CAUSE PROCEDURE OR ACTION
The engine will not start. The fuel tank is empty. Fill fuel tank.
The battery is not fully charged. Charge battery.
The connections at the battery Check and tighten battery
are loose or they have corrosion. connections.
The starter system has a Check electrical circuit for
problem. starter.
--- Page 4 ---
Sheet 3: Disassembly/Reassembly (overhaul)
1. See Figure 3-14. Inspect the stem of each valve for wear. Use a micrometer to measure the outside diameter of
the stem. The minimum dimension for an intake valve is 7.980 mm (0.3142 in). The minimum dimension for an
exhaust valve is 7.975 mm (0.3140 in).
2. Inspect the valves for cracks, burned faces and distortion. Inspect the seat face of the valves for wear and
damage. Measure the thickness of the valve head. See Figure 3-14. The minimum thickness for an intake valve
is 0.5 mm (0.020 in). The minimum thickness for an exhaust valve is 1.0 mm (0.040 in).
3. If the valves need grinding the correct surface angle is 30 degrees for both intake and exhaust valves.
VALVE SPRINGS
Check the valve springs for damage. See Figure 3-15. Measure the free length of the outer valve springs. The
minimum length of an intake spring is 44.3 mm (1.74 in) for the FE engine and 46.3 mm (1.823 in) for the F2 engine.
The minimum length of an exhaust spring is 50.8 mm (2.00 in) for the FE engine and 50.6 mm (1.992 in) for the F2
engine. Check the outer valve springs for being square. See Figure 3-15. If the measurement is more than 1.81 mm
(0.071 in), replace the valve spring(s).
Figure 3-15. Inspect The Valve Springs
Cylinder Head, Installation
1. Clean the surface of the cylinder head and the surface of the block.
2. Install a new cylinder head gasket to the block. Install the cylinder head.
3. Install the capscrews and washers for the cylinder head. Tighten the capscrews to 82 to 88 Nm (59 to 64 lbf
ft) as shown in Figure 3-16.
--- Page 5 ---
Sheet 3: Disassembly/Reassembly (overhaul)
2. Measure the clearance between the piston ring and the groove in the piston as shown in Figure 3-31. The
correct dimensions are as follows:
Top Piston Ring - 0.03 to 0.07 mm (0.0012 to 0.0028 in)
2nd Piston Ring - 0.03 to 0.07 mm (0.0012 to 0.0028 in)
Maximum clearance is 0.15 mm (0.0059 in)
Figure 3-31. Measuring The Piston Rings
1. PISTON RING END CLEARANCE
2. PISTON RING GROOVE CLEARANCE
CONNECTING RODS AND BEARINGS
1. Use a special machine to check the connecting rods for being straight. The maximum amount of distortion per
100 mm (4.0 in) is 0.04 mm (0.0016 in). If the amount of distortion is greater than the specification, use a press to
straighten the connecting rod.
2. Check the clearance between the rod bearings and the journals of the crankshaft. Clean the rod bearings and
journals. Use a plastic gauge material as shown in Figure 3-32. For the FE engine, tighten the capscrews for the rod
caps to 51 to 56 Nm (37 to 41 lbf ft). For the F2 engine, tighten the capscrews for the rod caps to 66 to 70 Nm (48 to
51 lbf ft). The correct clearance is 0.027 to
0.067 mm (0.0011 to 0.0026 in). If the clearance is greater than the specifications, replace the bearings.
--- Page 6 ---
Sheet 5: Cooling System
Figure 5-3. Timing Belt Covers
1. LOWER TIMING BELT COVER
2. UPPER TIMING BELT COVER
Figure 5-4. Water Pump
1. PULLEY
2. SHAFT AND BEARING ASSEMBLY
3. WASHER
4. HOUSING
5. SEAL
6. IMPELLER
Disassembly And Repair (See Figure 5-4.)
1. Use a puller to remove the pulley from the shaft.
2. Use a press to remove the impeller from the shaft and the bearing assembly from the housing. Remove the water
seal from the housing.
--- Page 7 ---
Sheet 6: Gasoline Fuel System
14. GASKETS
15. IDLE SOLENOID (FUEL SHUT-OFF)
16. IDLE MIXTURE SCREW
17. THROTTLE BODY
18. CHOKE ACTUATOR ASSEMBLY
19. CHOKE RELEASE
11. Remove the four screws and washers from the cover of the accelerator pump. Carefully remove the cover,
diaphragm and return spring from the float bowl housing.
12. Remove the idle control actuator and the solenoid valve from the float bowl housing.
13. Remove the idle mixture screw and spring from the throttle body.
Cleaning
WARNING
The solvent for cleaning carburetors is very flammable. Carefully follow the instructions of the
manufacturer.
WARNING
Compressed air can cause small particles to enter your skin. Always wear protective goggles when using
compressed air.
CAUTION
Do not use cleaning solvent to clean the float, choke diaphragm, accelerator pump diaphragm, solenoid
valve and the idle control actuator. Do not use cleaning fluid on the 0-rings at the idle compensa-tor port
and the accelerator pump nozzle. Remove the 0-rings before cleaning the carburetor. Be careful when
cleaning the plastic and nylon parts on the carburetor. Follow the instructions of the cleaning solvent
manufacturer for cleaning plastic and nylon.
CAUTION
Do not use a wire brush to clean any parts of the carburetor. Do not use a drill or wire to clean the lets or
passages of the carburetor.
Dirt or water inside or outside the carburetor is often the cause of carburetor problems. It is important that the
carburetor be completely cleaned before assembly.
Wash all the metal carburetor parts with a carburetor cleaning solvent. Use compressed air to clean the jets and
passages of the carburetor. Do not use compressed air on the diaphragms.
Use a clean cloth for cleaning the parts that cannot be cleaned in solvent.
Inspection
Inspect the carburetor parts for correct operation, wear or damage. Replace the carburetor parts or the carburetor as
necessary.
1. Inspect the carburetor body for cracks, distortion or other damage. Inspect each gasket surface for damage.
2. Inspect the choke plate, shaft and linkage for wear and damage. Check for rough edges on the choke plate. Make
sure the choke plate moves freely. Inspect the choke return springs for distortion and damage. Inspect the vacuum
break diaphragm and return spring for damage.
3. Inspect the throttle plate, shaft and linkage for wear or damage. Check for rough edges on the throttle plate. Make
sure the throttle plate moves freely. Inspect the throttle bushings and return springs for damage.
4. Inspect the accelerator pump diaphragm and return spring for damage. Make sure the passage in the accelerator
pump nozzle is open.
5. Check the operation of the power valve and piston. The power valve and piston must move freely in their bores.
Make sure the piston and the piston bore are clean. Check the piston spring for damage. Inspect the spring and
retainer clip on the power valve for damage.
6. Inspect the idle compensator valve and 0-ring for damage. Check the metal spring for damage. Replace the valve
if it is in the open position.
--- Page 8 ---
Sheet 6: Gasoline Fuel System
6-16
--- Page 10 ---
Sheet 7: L.P.G. Fuel System--Part 1
Figure 7-8. Parts Of The Vaporizer
1. SCREW
2. COVER FOR VAPOR VALVE DIAPHRAGM
3. VAPOR VALVE DIAPHRAGM
4. VAPOR VALVE LEVER
5. PIVOT PIN
6. SPRING
7. VAPORVALVE PAD
8. PIN
9. HOUSING
10. PAD FOR PRESSURE REDUCER VALVE
11. GASKET
12. PLATE
13. PLUG
14. ACTUATING PIN
15. DIAPHRAGM FOR PRESSURE REDUCER VALVE
16. COVER
A balance line connects the air pressure side of the va-por diaphragm to an air inlet port at the carburetor. If the air
filter has a restriction, the pressure decreases in the carburetor and in the vapor chamber of the vaporizer. When a
balance line is not installed, this decrease can cause the diaphragm to move and open the vapor valve. When a
balance tube is connected, the restriction causes an equal decrease on both sides of the dia-phragm. The balance
line prevents an increase in the fuel mixture in the carburetor. A button in the housing can be used to manually open
the vapor valve. LPG va-por then flows to the carburetor for starting the engine.
Removal
--- Page 11 ---
Sheet 7: L.P.G. Fuel System--Part 1
Idle Speed, "Closed Loop System' FE/F2 Engine 0.0% @ 700 rpm, 0.05% @ 750 rpm
Governed Speed, Standard FE/F2 Engine 0.30% @ 2600 rpm, 0.80% @ 2700 rpm (No Load)
System
Governed Speed, "Closed Loop FE/F2 Engine 0.0% @ 2600 rpm, 0.08% @ 2700 rpm (No Load)
System'
Tilt Relief, Standard System FE Engine 0.20% @ 2400 rpm
F2 Engine 0.20% @ 2520 rpm
Tilt Relief, "Closed Loop System' FE Engine 0.0% @ 2400 rpm
F2 Engine 0.0% @ 2520 rpm
Stall (Torque Converter), Standard FE Engine 1.70% @ 1930 rpm, 2.30% @ 2050 rpm
System F2 Engine 1.7% @ 2100 rpm, 2.30% @ 2200 rpm
Stall (Torque Converter), "Closed FE Engine 0.0% @ 1930 rpm, .23% @ 2050 rpm
Loop System' F2 Engine 0.0% @ 2100 rpm, .23% @ 2200 rpm
4. Adjust the idle control actuator as follows:
a. Run the engine until it is at normal operating tem-perature. Adjust idle speed and mixture as
de-scribed in Step 2 or 3 above.
b. Adjust the idle control screw (3) until there is 0.10 to 0.20 mm (0.004 to 0.008 in) clearance between
the idle control screw and the actuator rod (4).
c. Disconnect the vacuum hose (6) at the idle con-trol actuator (5). Put a plug in the hose. Check the
speed of the engine. If speed is below 1400 30 rpm, no further adjustment is needed. If the speed is above
1400 30 rpm, adjust the idle control screw (3) until the engine speed is correct.
SOLENOID VALVE (See Figure 7-1.)
The solenoid valve is installed at the fuel inlet of the car-buretor. The valve opens to let fuel to the carburetor when
the key switch is ON. When the key switch is OFF, the valve closes and fuel cannot flow to the carburetor.
The solenoid valve cannot be repaired. If the solenoid valve does not operate it must be replaced.
1. Disconnect the hose from the air cleaner to the carbu-retor inlet. Remove the fuel inlet hose. Disconnect the wires
at the solenoid valve. Remove the solenoid valve.
2. Use a liquid thread sealant and install the solenoid valve on the carburetor. Connect the wires and fuel hose.
Connect the hose to the air cleaner. Turn the key switch ON and OFF to check the operation of the sole-noid valve.
Start the engine and check for leaks.
3. Check all fittings for leaks with a soap and water solu-tion. Make sure there is a minimum of 620 kPa (90 psi) in
the system.
GOVERNOR (See Figure 7-16.)
The governor is installed between the carburetor and the intake manifold. The governor helps control the maximum
speed of the engine.
Figure 7-16. Governor
1. SECONDARY ADJUSTMENT SCREW
2. ADJUSTMENT SPRING
3. MAIN ADJUSTMENT WHEEL
4. LOCK SCREW AND WASHERS
--- Page 12 ---
Sheet 7: L.P.G. Fuel System--Part 1
the diaphragm in chamber C to expand and open the inlet valve between chambers B and C. This causes the
pressure to drop in chamber B and relaxes the diaphragm in chamber B. This opens the inlet valve between
chambers A and B. Fuel is supplied to the carburetor through chamber C, the idle bypass valve, and chamber D.
RESONATOR (See Figure 7-19., and Figure 7-21. through Figure 7-23.)
The resonator is connected by vacuum hoses to a special orifice fitting on the air filter discharge elbow (see Figure
7-19.) and to the resonator port of the regulator (see Figure 7-21.). The resonator port connects to vacuum chamber
2 (see Figure 7-23.).
As the air filter clogs, the intake vacuum increases for any relative throttle position. This increased vacuum has a
similar increase in the vacuum of chambers C and 2. By increasing the vacuum of chambers C and 2 by the same
level as the intake restriction, a balance is maintained and the relative position of the diaphragms remains
unchanged. See Figure 7-23. This maintains a constant fuel mixture regardless of the air filter restriction.
Figure 7-22. Resonator
Legend for Figure 7-22.
1.PLUG
2.CLIP
The special orifice fitting and the resonator act as vacuum dampeners. The air being drawn through the intake
system does not flow in a constant stream, but rather in small pulses generated during the intake stroke of the
pistons. Without the resonator and orifice, these pulses could be generated at a frequency that is a natural harmonic
of the diaphragms. This would cause the diaphragm to vibrate uncontrollably and force the engine mixture to be
either very rich or lean under certain operating conditions.
--- Page 13 ---
Sheet 7: L.P.G. Fuel System--Part 1
screws alternately to 3.9 0.5 Nm (34.5 4.5 lbf in). If this is a new regulator assembly, check and adjust according to
the procedures in the CHECKS AND ADJUSTMENTS section in this manual.
4. Install the diaphragm as noted during disassembly. Install the cover and four screws on the main housing.
Tighten the screws to 3.9 0.5 Nm (34.5 4.5 lbf in) in the order shown in Figure 7-29.
Figure 7-29.Diaphragm Cover Tightening Sequence
Figure 7-30. Alignment Pin Installation
5. Install the valve assembly in the main housing. Install the lever assembly and tighten the two screws alternately to
3.9 0.5 Nm (34.5 4.5 lbf in).
6. Position the diaphragm as noted during disassembly. Install the diaprhagm by hooking the shaft to the lever
assembly. Install the four alignment pins in the main housing as shown in Figure 7-30.
7. Install the 0-ring, the spring, the fuel filter chamber, and three screws on the main housing. Do NOT tighten the
three screws.
8 Remove the four alignment pins and install the four remaining screws. Tighten the seven screws to 3.9 0.5 Nm
(34.5 4.5 lbf in) in the order shown in Figure 7-31.
--- Page 14 ---
Sheet 8: L.P.G. Fuel System--Part 2
(See Figure 7-42. and Figure 7-43.)
Slowly move the foot directional control pedal pad from Forward to Reverse and back to Forward. There must be
some movement of the pedal pad before the pedal frame moves and the throttle opens.
ADJUST THE THROTTLE LINKAGE, GC 040-065 RF/TF and GC/GLC 040-065 RG/TG/ZG
(See Figure 7-43.)
NOTE: Each time the throttle linkage is disassembled, it is important to adjust the throttle cable.
1. Connect the throttle cable at the pedal. Tighten the jam nut at the pedal bracket.
2. Adjust the idle speed of the engine with the idle adjusting screw on the carburetor. The correct idle speed is 725
25 RPM.
3. Adjust the pedal height to 41.3 mm (1.63 in) using the pedal stop.
4. Connect the cable at the carburetor. Adjust the length of the cable housing so that the cable is not loose. With
the engine running at the correct idle speed, change the position of the cable housing with the nuts at the
bracket.
Figure 7-43. Throttle Arrangement, GC 040-065 RF/TF and GC/GLC 040-065 RG/TG/ZG
Legend for Figure 7-43.
1. PEDALPAD
2. PEDAL FRAME
3. LINK
4. PEDAL STOP
5. CRANK
6. PEDAL HEIGHT
7. PEDAL BRACKET
8. THROTTLE CABLE
Linkage Connections for Figure 7-43.
A = All Units
B = Gasoline/LPG Units
C = Diesel Units
--- Page 15 ---
Sheet 8: L.P.G. Fuel System--Part 2
When the throttle valve is opened slightly, the demand for fuel at the carburetor causes a slight vacuum at the output
port of the regulator. This vacuum causes the diaphragm in chamber C to depress. This opens the inlet valve
between chambers B and C, allowing fuel to flow from chamber B to chamber C. This allows large amounts of fuel to
flow to the carburetor for complete combustion.
Idle Mode
See Figure 7-48. In the idle mode, the demand for fuel at the carburetor is low and the vacuum is absent at the fuel
outlet port. This causes the diaphragm in chamber C to relax and close the inlet valve between chambers B and C.
Pressure in chamber B builds up to 24.5 to 34.5 kPa (7.2 to 10.1 inHg), causing the diaphragm in chamber B to
expand and close off the fuel supply. A balance is reached between the amount of vaporizing (liquid) through
chamber A and amount of vapor escaping past the idle mixture adjusting screw in chamber D.
The idle mixture adjusting screw is set for a lean mixture at the factory. The fuel injector supplies additional fuel to
the carburetor at idle. The ECU controls the fuel injector by using inputs from the oxygen sensor and vacuum switch
#1.
Run Mode
See Figure 7-48. In the run mode, the throttle valve on the carburetor is opened, creating a vacuum at the fuel outlet
port. This causes the diaphragm in chamber C to expand and open the inlet valve between chambers B and C. This
causes the pressure to drop in chamber B and relaxes the diaphragm in chamber B. This opens the inlet valve
between chambers A and B. Fuel is supplied to the carburetor through chamber C, the idle bypass valve, and
chamber D.
RESONATOR
(See Figure 7-44., and Figure 7-46. through Figure 7-48.)
The resonator is connected by vacuum hoses to a special orifice fitting on the air filter discharge elbow (see Figure
7-44.) and to the resonator port of the regulator (see Figure 7-46.). The resonator port connects to vacuum chamber
2 (see Figure 7-48.).
Figure 7-47. Resonator
As the air filter clogs, the intake vacuum increases for any relative throttle position. This increased vacuum has a
similar increase in the vacuum of chambers C and 2. By increasing the vacuum of chambers C and 2 by the same
level as the intake restriction, a balance is maintained and the relative position of the diaphragms remains
unchanged. See Figure 7-48. This maintains a constant fuel mixture regardless of the air filter restriction.
The special orifice fitting and the resonator act as vacuum dampeners. The air being drawn through the intake
--- Page 16 ---
Sheet 8: L.P.G. Fuel System--Part 2
Tighten the sensor to 39 Nm (29 lbf ft).
VACUUM SWITCHES
NOTE: Vacuum switch #1 has a white body with a gray top. Vacuum switch #2 has a white body with a
white top. This procedure is used for both switches.
Removal and Installation
1. Disconnect the vacuum hose.
2. Disconnect the electrical connector from the vacuum switch.
3. Remove the mounting clamp and the capscrew. Remove the vacuum switch.
4. Install the switch in reverse order.
Figure 7-53. Vacuum Switches
Legend for Figure 7-53.
1. VACUUM SWITCH #1 (IDLE)
2. VACUUM SWITCH #2 (WIDE-OPEN THROTTLE)
3. CARBURETOR
Inspection
1. Connect an ohm meter to the vacuum switch.
2. Apply a vacuum to the switch. The contacts of vacuum switch #1 should close at -29.0 to -33.3 kPa
(-8.5 to -9.8 in Hg). The contacts of vacuum switch #2 should close at -16.0 to -20.0 kPa (-4.7 to -5.9 inHg).
3. Release the vacuum. The switch contacts should open.
RESISTOR
Removal and Installation
Disconnect the electrical connector. Then remove the mounting screw and the resistor. Install the resistor in reverse
order.
Inspection
Use an ohm meter to check the resistor for continuity. The coil resistance should be 5.4 to 6.6 ~.
CHECKS AND ADJUSTMENTS
ADJUST THE CARBURETOR AND NEW REGULATOR
Idle Speed and Fuel Mixture (See Figure 7-54.)
WARNING
--- Page 17 ---
Sheet 8: L.P.G. Fuel System--Part 2
The idle mixture adjusting screw is Replace the regulator.
clogged with tar.
The fuel injector is clogged with tar. Clean the fuel injector.
The engine does not idle The resonator hose is either Replace a damaged hose or
smoothly. damaged or disconnected. reconnect a disconnected
(Rich fuel/air mixture) hose.
The resonator is damaged. Replace the resonator.
The fuel injector pulse rate does Check fuel injector and wiring,
not drop at idle. vacuum hose, vacuum switch
#1, oxygen sensor, and ECU.
The idle mixture adjusting screw on Replace the regulator.
the regulator is out of adjustment.
The engine does not idle The idle air bypass adjusting screw Clean or replace the idle air
smoothly. on the carburetor may be clogged. bypass adjusting screw and
(Idle speed too low) clean the tar from the
carburetor.
The idle air bypass adjusting screw Perform the adjustment
on the carburetor is out of procedures located in
adjustment. Checks and Adjustments.
The idle mixture adjusting screw on Replace the regulator.
the regulator is out of adjustment.
The engine does not idle The idle air bypass adjusting screw Perform the adjustment
smoothly. on the carburetor is out of procedures located in
(Idle speed too high) adjustment. Checks and Adjustments.
The idle mixture adjusting screw on Replace the regulator.
the regulator is out of adjustment.
TROUBLESHOOTING
PROBLEM POSSIBLE CAUSE CORRECTIVE ACTION
There is engine hesitation, A vacuum hose is either damaged Replace a damaged hose or
surge, knocking, or loss of or disconnected. reconnect a disconnected
power due to lean or rich hose.
fuel/air mixture.
The main fuel shutoff solenoid Clean the main fuel shutoff
valve is clogged. solenoid valve.
The idle fuel shutoff solenoid valve Clean the idle fuel shutoff
is clogged. solenoid valve.
The fuel hose is damaged. Replace the fuel hose.
The fuel filter is clogged. Replace the fuel filter and
clean the tar from the
regulator.
The idle mixture adjusting screw Clean or replace the
may be clogged. regulator as necessary.
There is tar accumulation in the Remove the drain plug and
regulator. drain the tar from the
regulator.
There is an air leak between the Replace the gasket if it is
carburetor and governor. broken or tighten the
mounting nuts to the correct
torque.
The carburetor is out of calibration. Perform the checking
procedure located in Checks
and Adjustments. If out of
calibration, replace the
carburetor.
The idle mixture adjusting screw Replace the regulator.
may be out of adjustment.