TM 5-4310-335-14
Table 5-1. TROUBLESHOOTING (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Adjust the governor.
a. Remove the front throttle housing cover and gasket.
b. Open clevis end disconnect it from the throttle lever.
c. Hold the throttle 1/16 inch from the open position.
d. Loosen the locknut below the clevis and screw the clevis up or down until the clevis pin aligns with the
hole in the throttle lever.
e. Connect the clevis to the throttle lever and tighten locknut.
f. Install the gasket and front throttle housing cover.
g. To regulate engine speed, turn nut on control rod assembly clockwise to increase or counterclockwise
to decrease engine speed.
NOTE
Eliminate surging or poor speed regulation by adjusting the idle adjustment needle
on the carburetor.
Connect ignition switch leads. Install the flywheel cover. Install the spark plug.
Install the rocker arm cover, using a new gasket. Install the side cylinder cover.
Step 2. Check for a broken piston, piston rings excessively worn, broken, or stuck.
Remove cylinder head and valve mechanism as follows:
a. Remove nuts (4).
b. Remove clip and slide shaft from cylinder head.
e. Remove nut and adjusting screw.
d. Remove push rod housing.
NOTE
Remove push rods and packing from housings.
a. Remove cylinder head.
NOTE
Remove and discard cylinder head gasket.
NOTE
Remove needle bearings from rocker arm shaft.
Drain crankcase oil. Remove twelve screws and remove oil pan. Remove and
discard oil pan gasket. Rend washer tango out and remove connecting rod bolt and
oil dipper bolt. Remove connecting rod cap and discard washer. Remove piston
and connecting rod assembly. Disassemble the piston and connecting rod
assembly.
WARNING
Dry cleaning solvent, P-D-680 or P-S-661, used to clean parts is potentially
dangerous to personnel and property. Avoid repeated and prolonged skin
contact. Do not use near open flame or excessive heat. Flash point of
solvent is 100 (39 ) - 138 (59 ).
F
C
F
C
Clean all parts with dry cleaning solvent P-D680.
Remove carbon deposits from piston grooves and clean out the carbon, sludge, and grim
deposits from ring grooves. Clean the other parts thoroughly and dry with compressed
filtered air. Inspect pistons for cracks and scoring. Measure the diameter across the
smallest point using a micrometer. Measure the piston ring groove for wear. Replace
parts if damaged or defective. Inspect rings for excessive wear and gap clearance.
Replace defective rings. Inspect piston pins for wear and damage. Check clearance
between piston pins end pistons.
Inspect connecting rod for cracked or warped condition. Check connecting red clearance
to the crankshaft journals. Replace a defective connecting rod. Reassemble the piston
and connecting rod assembly. Use a ring expander and install the piston rings.
NOTE
On installation of the connecting rod and piston into the engine, be sure to rotate
the crankshaft and check to see if the oil dipper bolt is on the correct side. If the oil
dipper bolt stops the rotation of the crankshaft, it is on the wrong side. Change
holes with the connecting rod bolt and crankshaft should rotate.
Install connecting rod and piston into the engine. Use new lockwasher under the
connecting rod bolt and oil dipper bolt. Bend tangs of washer up to bolt heads. Replace
the oil pan gasket and oil pan. Use proper torque on oil pan capscrews.
Refer to Step 1 and install the cylinder head and valve mechanism.
5-3
