TM 5-4310-335-14
Table 5-1. TROUBLESHOOTING (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
2. ENGINE OIL CONSUMPTION EXCESSIVE
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
Step 1. Check piston rings for wear or stuck.
Refer to Step 1 of Malfunction 1 and remove cylinder head and valve mechanism. Drain crankcase oil.
Remove eight screws and remove oil pan. Remove and discard oil pan gasket. Bend washer tangs
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-.D.680. Remove carbon deposits from
piston grooves and clean out the carbon, sludge, and gum 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 and pistons. Inspect connecting rod for cracked or
warped condition. Check connecting rod 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.
Step 2. Check front and rear oil seals for oil seepage or leakage.
Remove flywheel cover.
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
Remove starter flange retaining screws and remove starter flange.
Bend
lockwasher tang down on flywheel retaining nut and remove flywheel retaining nut.
Using a suitable puller, remove the flywheel. Remove the rotor, coil, and noise
filter. Using a suitable puller, remove the front crankshaft oil seal. Remove the
rear seal in the same manner. Clean the parts with dry cleaning solvent P-D-680
and dry thoroughly with compressed air. Dry the coil and rotor with a clean cloth.
Before installation, inspect rotor for burned or pitted contacts, wear, alignment, and
worn bearing. Inspect for damaged, cracked insulation, loose rivets and spring coil
clamps. inspect coil and wires for continuity or breaks. Replace any defective part.
3. ENGINE EXCESSIVELY NOISY
Step 1 Check for broken valve spring or bent valve.
Remove five screws and remove the two side cylinder head covers. Remove the rocker arms cover
retaining screw and remove the rocker arm cover. Remove the rocker arm cover gasket and discard.
Remove the spark plug. Remove the flywheel fan cover. Remove carburetor and throttle controls, as
follows:
a. Remove screw (2) and remove throttle control housing cover.
b. Remove screw and disconnect throttle lever from shaft.
c. Remove nut (2) and remove carburetor and gasket from intake manifold.
5-4
