Mercury MERCRUISER, Service Manual, Page: 270 / 566

Main Bearings, Without Crankshaft Removed
Installation
1. Remove the cap on the main bearing requiring replacement.
2. Remove the bearing from the cap.
3. Install the main bearing remover and installer tool in the oil hole in the crankshaft journal. If this tool is not available, a
cotter pin may be bent as shown and used.
a - Main bearing remover and
installer tool
b - Cotter pin
Description Part Number
Kent‑Moore main bearing remover and installer tool J8080
4. Rotate the crankshaft clockwise as viewed from the front of the engine. This will roll the upper bearing out of the engine
block.
5. Lubricate a new upper bearing.
6. Insert the plain (unnotched) end between the crankshaft and the indented or notched side of the engine block.
7. Rotate the bearing into place and remove the tool from the oil hole in the crankshaft journal.
8. Lubricate a new lower bearing and install in the bearing cap.
Tube Ref No. Description Where Used Part No.
136
Lubriplate SPO 255 Upper and lower bearing Obtain Locally
9. Install the main bearing cap in the original location with the markings pointing toward the front of the engine.
a - Main bearing cap
b - Bearing cap marks
10. Tighten all main bearing caps, except the rear main bearing cap.
Description Nm lb‑in. lb‑ft
Crankshaft main bearing cap bolt—preferred method
First torque
25 – 18.4
Final torque
+90°
11. Tighten the rear main bearing cap. Using the method described below.
Preferred Method:
a
b
6379
a
b
55071
Engine Inspection and Assembly
Page 3B-68 © 2016 Mercury Marine 90-8M0099748 eng DECEMBER 2015