3135990A1 Mercury MerCruiser Bearing | Genuine Quicksilver OEM Part

🔧 Product Description

Genuine Quicksilver Roller Bearing Assembly - Part Number: 31-35990A1

A genuine Quicksilver roller bearing assembly used across early MerCruiser I, R, MR, Alpha One, Alpha One Gen II, TR / TRS and Vazer drive applications. This bearing is commonly associated with specific MerCruiser gear ratios including 1.65 / 1.62, 1.84 / 1.81 and 1.98 / 1.94 applications.

⚙️ Key Features

• Genuine Quicksilver OEM bearing assembly

• Correct Mercury part number 31-35990A1

• Tapered roller bearing assembly

• Used in multiple MerCruiser stern drive bearing applications

• Commonly suits I, R, MR, Alpha One and Alpha One Gen II drives with selected ratios

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 31-35990A1 current OEM bearing assembly reference

OEM / Related Numbers:

• 31-35990A1

• 35990A1

• 3135990A1

• 31-35990A 1

Aftermarket / Verified Equivalents:

• Sierra: 18-1161

• GLM: 21540

• SEI Marine: 93-102-04

• Red Rhino: R-89449

• OMC Stern Drive cross-reference: 983891 where specified

🚤 Compatibility

Commonly used on:

• MerCruiser I / R / MR / Alpha One and Alpha One Gen II sterndrive bearing applications

• MerCruiser TR / TRS and Vazer drive applications where specified

Typically suits:

• Drive / ratio models:

• MerCruiser 120 / 140 stern drive - 1967-1969

• MerCruiser 120 / 140 / 165 stern drive - 1970-1977

• MerCruiser 120 / 140, 1.98 ratio - 1970-1977

• MerCruiser 165, 1.65 ratio - 1970-1977

• MerCruiser 470 / 485, 1.84 ratio applications

• MerCruiser 260 / 898 / 228, 1.50 ratio applications

• MerCruiser 898 stern drive - 1978-1982

• MerCruiser 485 stern drive - 1980-1982

• MerCruiser 225-S / 233, 1.32 ratio stern drive - 1974-1977

• MerCruiser 888 stern drive, 1.50 ratio - 1971-1977

• MerCruiser IA / IB / IC stern drives - 1964

• MerCruiser IA / IB / IC EZ-Shift - 1965-1966

• MerCruiser R / MR / Alpha One sterndrive - 1983-1990

• MerCruiser R / MR / Alpha One transom assembly - 1983-1990

• MerCruiser Alpha One Gen II sterndrive and transom assembly - 1991-1995

• MerCruiser Alpha One Gen II sterndrive and transom assembly - 1996-1997

• MerCruiser Alpha One Gen II sterndrive and transom assembly - 1998 and up

• MerCruiser TR / TRS stern drive - 1977-1993

• MerCruiser 255 TRS - 1973-1974

• MerCruiser 280 TRS - 1975-1976

• MerCruiser Vazer drive / Vazer transom applications where 31-35990A1 is specified

• Drive Type: MerCruiser I / R / MR / Alpha One / Alpha One Gen II / TR / TRS / Vazer

• Ratio Notes: Commonly used on 1.65 / 1.62, 1.84 / 1.81 and 1.98 / 1.94 ratio applications

• System Type: Sterndrive roller bearing assembly

🔌 Function

The bearing supports rotating gear and shaft components inside the sterndrive, helping maintain correct alignment and load support.

Common signs of failure:

• Drive whine or growling noise

• Rough bearing feel during rebuild

• Metal contamination in gear oil

• Shaft movement or preload issue

• Bearing replacement required during upper / lower drive service

📦 Condition

• Genuine Quicksilver part

• Brand new

• Supplied in original or equivalent packaging