Mercury 200 OptiMax Jet Drive, Service Manual, Page: 307 / 391

Powerhead
Page 4A-42 90-8M0050731 MAY 2011
5. Clean the crankshaft surfaces with crocus cloth.
a - Crankshaft journals
b - Crocus cloth
6. Thoroughly clean the crankshaft with a mild solvent and dry with compressed air. Replace the crankshaft if the bearing
surfaces are damaged and cannot be properly cleaned up. Lubricate the surfaces of the crankshaft with light oil to prevent
rust. Do not lubricate the crankshaft ball bearing at this time.
!
WARNING
Spin‑drying bearings with compressed air can cause serious injury or death. The bearings can explode, even if spun at very
slow speeds. Do not allow the bearings to spin when drying with compressed air.
Crankshaft and End Cap Bearings
IMPORTANT: When overhauling the powerhead assembly, replace all crankshaft bearings; upper/lower, center main, connecting
rod, and wrist pin bearings. This ensures optimum powerhead performance and longevity.
1. After cleaning the crankshaft, grasp the outer race of the crankshaft ball bearing installed on the lower end of the crankshaft
and work the race back and forth. There should not be excessive play.
2. Lubricate the ball bearing with light oil. Rotate the outer bearing race. The bearing should have smooth action and no rust
stains. If the ball bearing sounds or feels rough, or has catches, remove and discard the bearing.
a - Lower crankshaft ball bearing
3. Thoroughly clean and dry the crankshaft center main roller bearings. Lubricate the bearings with 2‑Cycle Premium Outboard
Oil.
Tube Ref No. Description Where Used Part No.
14
2-cycle Premium
Outboard Oil
Main bearings 92-858021K01
!
WARNING
Spin‑drying bearings with compressed air can cause serious injury or death. The bearings can explode, even if spun at very
slow speeds. Do not allow the bearings to spin when drying with compressed air.
IMPORTANT: The crankshaft bearings are matched sets. Mismatching the bearings can result in engine damage. Replace
and install the bearings in matched pairs.
b
a
8683
a
8684