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10
10
CRANKSHAFTS AND CAMSHAFTS
Remove Crankshaft and Camshaft
1. Drain oil from engine and all fuel from fuel
tank. Drain oil from gear reduction unit (if
equipped) and remove from engine
(A, Figure 1).
2. Remove blower housing/rewind assembly
and flywheel/fan assembly.
3. Remove burrs and clean crankshaft, then
remove crankcase cover or sump. Set
aside.
NOTE: If crankcase cover or sump sticks, tap
lightly with soft hammer on alternate sides near
dowel pins (B). It is not necessary to remove
dowel pins.
Figure 1
4. Carefully tip engine with PTO-end facing
up.
5. Rotate crankshft until timing marks
(A, Figure 2) are aligned. With camshaft in
this position, the valve tappets will remain
clear of cam lobes. Lift out camshaft (B).
Figure 2
6. Rotate crankshaft to place piston at Top
Dead Center (TDC).
7. Remove connecting rod cap, then slide out
crankshaft.
Inspect
Check Crankshaft
1. Inspect crankshaft for scoring on mag
journal (A, Figure 3), crankpin journal (B),
and PTO journal (C). Replace crankshaft
is scoring is found or if crankshaft is bent.
DO NOT attempt to straighten bent
crankshafts.
Figure 3
2. Using a dial caliper, measure the journal
diameters and balancer eccentrics (if
equipped). Compare results to values
listed in Section 12 - Engine
Specifications. If wear exceeds the reject
dimensions, replace the crankshaft.
Check Camshaft
1. Check gear (A, Figure 4) for worn or
damaged teeth. Check lobes (D) and
journals (B, C) for scratching or scoring.
Check compression release mechanism
(A, Figure 5) for wear, burrs, or sticking.
Replace camshaft if any of these
conditions are found.