Mercury 40 Service Manual page 265

CYLINDER BLOCK/CRANKCASE
7. Remove the crankcase cover. Measure the compressed plastigauge to check the main
bearing clearance. Replace bearings if clearance is not in specification.
8. If replacement of the main bearings is required, refer to Main Bearing Selection and
Installation in Cylinder Block Reassembly.
Checking Connecting Rod Bearing Clearance
IMPORTANT: Do not interchange used connecting rod bearings. Reinstall bearings
in their original position.
1. Clean all the oil from the connecting rod bearing surfaces and connecting rod journals
on the crankshaft.
NOTE: Refer to instructions in Cylinder Block Reassembly for selecting and installing con-
necting rod bearings.
2. Place a piece of plastigauge on the connecting rod journals.
a -
IMPORTANT: Do not rotate connecting rod when checking clearance.
Page 4B-24
Main Bearing Clearance
0.0005 - 0.0017 in. (0.012 - 0.044 mm)
a
Plastigauge
53751
53751
90-828631R3 MARCH 1999