SIERRA MerCruiser Alpha One Gen II Tapered Roller Bearing – 18-1143

Description

SIERRA MerCruiser Alpha One Gen II Tapered Roller Bearing – 18-1143

Tapered roller bearing for selected MerCruiser Alpha One Gen II gearcases. It is used in the lower-drive gear train where controlled radial and thrust loading is required during propeller-shaft and gear operation.

• Tapered roller bearing
• For Alpha-family lower-unit gear train service
• Carries combined radial and thrust loads
• Replace damaged race/cup components as required
• Verify gear ratio and serial number before ordering

For marine engine and drive parts, fitment can vary by serial number, gear ratio, casting, or prior service history. Compare the original part number and physical configuration before installation; replace related gaskets, seals, races or hardware when their condition requires it.

Specifications

• Manufacturer: Sierra
• Part Number: 18-1143
• Application: Selected Alpha One Gen II lower units, commonly 1.50-1.65 ratio applications; verify serial number and gearset.

Interchange / OEM References

• MerCruiser 31-36387A1
• GLM 21580
• Mallory 9-75107