30-72961 Mercury MerCruiser Bearing T12505 | Genuine Quicksilver OEM Part

🔧 Product Description

Genuine Quicksilver Ball Bearing - Part Number: 30-72961

A genuine Quicksilver ball bearing used in selected Mercury outboard crankcase applications and MerCruiser belt-driven sea water pump assemblies. This bearing supports the rotating shaft inside the specified pump or crankcase assembly, helping maintain smooth rotation and correct load support.

⚙️ Key Features

• Genuine Quicksilver OEM ball bearing

• Correct Mercury part number 30-72961

• Replacement for selected Mercury and MerCruiser water pump / crankcase bearing locations

• Cross-references with Sierra 18-1398

• Also associated with earlier Mercury 30-20861 bearing reference

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 30-72961 → Supersedes 30-20861

• 30-20861 earlier OEM ball bearing reference

OEM / Related Numbers:

• 30-72961

• 72961

• T12505 bearing reference

• 30-20861

• 20861

Aftermarket / Verified Equivalents:

• Sierra: 18-1398

• GLM: 21625

• Mallory: 9-43220

🚤 Compatibility

Commonly used on:

• Mercury 3.5HP to 9.8HP outboard crankcase / bearing applications

• MerCruiser belt-driven sea water pump shaft bearing applications

Typically suits:

• Engine / pump models:

• Mercury 7.5HP outboard - serial 5206550 and up

• Mercury 7.5HP outboard - serial 7125388 and up

• Mercury 7.5HP outboard - serial 8057545 and up

• Mercury 7.5HP outboard - serial 9217756 and up

• Mercury 9.8HP outboard - serial 5206550 and up

• Mercury 9.8HP outboard - serial 7127388 and up

• Mercury 9.8HP outboard - serial 8057545 and up

• Mercury 9.8HP outboard - serial 9217756 and up

• Mercury Merc 7.5J - serial 85A1101 and up

• Mercury / MerCruiser 3.5HP to 9.8HP small outboard bearing applications where 30-72961 is specified

• MerCruiser 470 2BBL Mercury 224 I/L4 - 1980-1982, serial 5520115 to 6218036

• MerCruiser 470 MIE Mercury 224 I/L4 - 1980-1981, serial 5520115 to 6218036

• MerCruiser 280 TRS GM 350 V8 - 1975-1976, serial 4176250 to 4770199

• MerCruiser belt-driven sea water pump assemblies using bearing 30-72961

• MerCruiser sea water pump shaft bearing applications using Sierra 18-1398 equivalent

• Engine Type: Mercury small outboard and MerCruiser petrol sterndrive / inboard water pump applications

• System Type: Ball bearing / crankcase or belt-driven sea water pump bearing

🔌 Function

The bearing supports shaft rotation inside the pump or crankcase assembly, reducing friction and keeping rotating parts aligned under load.

Common signs of failure:

• Growling or grinding from pump assembly

• Excessive shaft play

• Water pump leakage due to shaft movement

• Bearing roughness during pump rebuild

• Corrosion or seizure after water intrusion

📦 Condition

• Genuine Quicksilver part

• Brand new

• Supplied in original or equivalent packaging