Crankshaft Installation - Mercury 25 EFI Service Manual

5.
Ensure the UP mark on the top of the piston is towards the flywheel. Push the piston down into the cylinder bore until the
rings have entered the cylinder.
a
b
Tube Ref No.
10W-30 4-Stroke Marine
110
Engine Oil
Piston Ring Compressor
6. Repeat the procedure for the remaining cylinders.

Crankshaft Installation

1. Install crankshaft main bearings into the cylinder block and crankcase cover.
2. Lubricate the following areas generously with 4‑Stroke 10W‑30 Outboard Oil.
• Crankshaft seal and main bearing areas
• Crankshaft connecting rod journals
• Connecting rod bearing surfaces
• Connecting rod caps
3. Lubricate the upper and lower crankshaft seal lips with 10W‑30 4‑Stroke Marine Engine Oil. Slide the seals onto the
crankshaft ends.
4. Carefully place the crankshaft onto the crankshaft main bearings.
5. Ensure the crankshaft seals are centered in the seal area of the cylinder block.
a
b
Tube Ref No.
10W-30 4-Stroke Marine
110
Engine Oil
6. Assemble the connecting rods to the crankshaft and install the connecting rod caps.
7. Secure the connecting rod caps with two bolts. Tighten the connecting rod cap bolts in two steps to the specified torque.
90-8M0105568 eng MARCH 2016
a - Piston
b - Ring compressor tool firmly seated against the cylinder block
21019
Description
110
a
b
110
Description
Where Used
Piston, piston rings, and cylinder bore
a - Upper and lower crankshaft seals
b - Crankshaft main bearings
11733
Where Used
Connecting rod and crankshaft main bearings
© 2016 Mercury Marine
Cylinder Block/Crankcase
92-8M0078625
FT2997
92-8M0078625
Part No.
Part No.
Page 4A-21