MerCruiser GM4 Service Manual page 127

8. Install as previously outlined:
a. Oil pump.
b. Dipstick and oil pan.
c. Cylinder heads.
d. Intake manifold.
e. Distributor.
9. Fill crankcase with oil. Refer to SECTION 1 -
"Maintenance."
10. Torque rocker arm nuts to 20 lb. ft. (27 N·m).
Crankshaft
Removal
1. Remove engine from boat.
2. Drain crankcase oil.
3. Remove as outlined:
a. Starter.
b. Flywheel housing.
c. Drive coupler and flywheel.
d. Belts.
e. Water pump.
f. Crankshaft pulley and torsional damper.
g. Spark plugs.
h. Oil pan and dipstick tube.
i. Oil pump.
j. Timing chain cover.
4. Turn crankshaft to align timing mark with cam-
shaft mark.
5. Remove camshaft sprocket.
6. Remove rear main seal and retainer.
7. Ensure all bearing caps (main and connecting
rods) are marked so they can be reinstalled in
their original locations.
8. Remove connecting rod bearing caps, then push
piston and rod assemblies toward heads.
9. Remove main bearing caps and carefully lift
crankshaft out of cylinder block.
Index
90-816462 2-695
10. Remove crankshaft gear as shown.
11. If new main and/or connecting rod bearings are to
be installed, remove main bearing inserts from
cylinder block and bearing caps, and/or connect-
ing rod bearing inserts from connecting rod and
caps. Install new bearings following procedures
outlined.
Cleaning and Inspection
1. Wash crankshaft in solvent and dry with com-
pressed air.
2. Measure main bearing journals and crankpin di-
mensions with a micrometer for out-of-round, ta-
per or undersize (see "Specifications").
3. Check crankshaft for runout (by supporting at
front and rear main bearings journals in V-blocks)
and check at front and rear intermediate journals
with a dial indicator (see "Specifications").
4. Replace or recondition crankshaft if not within
specifications.
Installation
1. If a new crankshaft is being installed, remove tim-
ing sprocket from old crankshaft and reinstall on
new crankshaft as outlined.
IMPORTANT: Be sure that all bearings and crank-
shaft journals are clean.
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