Yanmar 1GM User Manual page 132

126
Camshaft
gear
d. Install a dial indicator as shown in Figure 63 and
measure crankshaft end play. Compare the mea-
surement with the specification in Tables 1-3. Ifend
play is incorrect, refer to the Main Bearings section
to determine the cause.
e. Align the timing marks (Figure 66) on the camshaft
and crankshaft gears when installing the crankshaft
gear.
f. Check timing gear backlash by installing a dial indi-
cator as shown in Figure 67 or by rotating the gear
teeth with soft solder between the gear teeth. Com-
pare the measurement with the specification in Ta-
bles 1-3. If gear backlash is incorrect, replace the
camshaft and crankshaft gears.
Inspection
1. Clean the crankshaft thoroughly with solvent. Blow
out the oil passages with compressed air.
2. Check the main and connecting rod journals for wear,
scratches, grooves, scoring or cracks. Check oil seal sur-
face for burrs, nicks or other sharp edges that might dam-
age a seal during installation.
NOTE
Unless precision measuring equipment is
available, have a machine shop perform
Step 3.
3. Check all journals against specifications (Tables 1-3)
for out-of-roundness and taper. Have the crankshaft
reground, ifnecessary, and install new undersize bearings.
CHAPTER SIX
MAIN BEARINGS
The crankshaft is supported at each end by insert-type
main bearings. The front main bearing is located in the
crankcase and the rear main bearing is located in the re-
movable main bearing carrier. The intermediate, in-
sert-type bearing is held in a removable bearing housing.
See Figure 61. Two intermediate bearings are used on
three-cylinder engines, while one intermediate bearing is
used on two-cylinder engines.
Crankshaft thrust (end play) is controlled by the inter-
mediate bearing on two-cylinder engines. On
three-cylinder engines, the intermediate bearing nearest
the flywheel controls crankshaft thrust.
Remove the crankshaft as described in the previous sec-
tion for access to the main bearings. Unless precision