478M0137221 Mercury MerCruiser Impeller Kit | Genuine Quicksilver OEM Part

🔧 Product Description

Genuine Quicksilver Heavy Duty Sea Water Pump Impeller Kit - Part Number: 47-8M0137221

Genuine Quicksilver/MerCruiser heavy duty sea water pump impeller kit for selected MerCruiser crankshaft-mounted sea water pump applications. This OEM kit is commonly used on MerCruiser 4.3L MPI, 5.0L MPI and 350 MAG MPI engines, and also suits selected 4.5L and 6.2L pump applications by serial range.

⚙️ Key Features

• Genuine Quicksilver/Mercury OEM heavy duty impeller kit

• Designed for selected MerCruiser crankshaft-mounted sea water pumps

• Includes impeller, gaskets, O-rings and service lubricant

• Used on selected MCM/MIE MPI engine packages

• Direct replacement for the 8M0121940 / 8M0137221 design II pump kit reference

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 47-8M0137221 → Supersedes 47-8M0121940

• 47-8M0121940 earlier OEM reference

OEM / Related Numbers:

• 47-8M0137221

• 8M0137221

• 478M0137221

• 47-8M0121940

• 8M0121940

• 98-8M0137221 related kit packaging / service reference

Aftermarket / Verified Equivalents:

• REC: REC98-8M0121940

• EMP: 47-09202 where matched to design II pump

• Sierra: Design II application equivalent where matched by pump assembly

🚤 Compatibility

Commonly used on:

• MerCruiser Design II crankshaft-mounted sea water pump assemblies

• MerCruiser MCM and MIE MPI engine packages

• Selected late-model 4.5L and 6.2L MerCruiser sea water pump applications by serial range

Typically suits:

• Engine models:

• MerCruiser MCM 4.3L MPI engines using the matching Design II sea water pump

• MerCruiser MIE 4.3L MPI engines using the matching Design II sea water pump

• MerCruiser MCM 5.0L MPI engines using the matching Design II sea water pump

• MerCruiser MIE 5.0L MPI engines using the matching Design II sea water pump

• MerCruiser MCM 350 MAG MPI engines using the matching Design II sea water pump

• MerCruiser MIE 350 MAG MPI engines using the matching Design II sea water pump

• MerCruiser 4.5L Bravo, serial 2A531163 and up

• MerCruiser 6.2L Bravo, serial 2A531197 and up

• MerCruiser 6.2L Inboard, serial 2A530774 and up

• MerCruiser 6.2L TowSport, serial 2A531348 and up

• HP Range: Application dependent across listed MerCruiser MPI, 4.5L and 6.2L petrol engine packages

• Engine Type: MerCruiser petrol stern drive / inboard crankshaft-mounted raw-water pump system

• Year Range: Late-model MerCruiser applications, dependent on pump design and serial number

🔌 Function

The sea water pump impeller kit services the crankshaft-mounted raw-water pump. The impeller draws water into the cooling system, while the included seals and gaskets help maintain pump sealing and water pressure.

Common signs of failure:

• Engine overheating

• Reduced raw-water flow

• Overheating at idle or under load

• Cracked, worn or missing impeller blades

• Water leaking from the pump body

• Rubber fragments in cooling passages

• Poor cooling after seasonal storage

📦 Condition

• Genuine Quicksilver part

• Brand new

• Supplied in original or equivalent packaging