Lower Unit Drain Plugs & Washers | Mercury Outboard

OEM and Cross Reference Numbers

Depending on manufacturer, catalog and aftermarket brand, this drain plug seal may be found under several different part numbers.

When replacing an existing seal, compare the original part number and verify the engine model or serial number before ordering.

What This Part is Used For

The 8M0082880 seal fits around the applicable lower-unit drain/fill screw. When the screw is tightened, the seal helps create a reliable barrier between the gearcase and the surrounding water.

A properly sealing drain screw is important because the lower unit needs to:

• Keep gear lubricant inside the gearcase
• Help prevent water from entering through the drain screw
• Maintain a reliable seal after routine gear-lube service

Mercury and Mariner Fitment

Mercury 8M0082880 appears in gearcase, driveshaft-housing and maintenance diagrams across a number of small Mercury outboard families. Applications shown in the supplied Mercury catalog information include the following.

Additional earlier Mercury applications are shown in the supplied catalog diagrams, including select carbureted 8, 9.9, 10, 15, 20 and 25 HP models and earlier 25/30 HP EFI applications. Because Mercury used multiple gearcase configurations within some horsepower families, verify the engine serial number and gearcase diagram when working with an earlier engine.

Johnson and Evinrude Fitment

Cross-reference data also identifies this seal for numerous Johnson and Evinrude 3-15 HP four-stroke model-number applications. Matching model families include:

The complete model suffix matters. When identifying this seal by Johnson or Evinrude model number, compare the complete engine model designation with the parts catalog rather than relying only on horsepower.

Nissan and Tohatsu Applications

Cross-reference information also shows this drain-plug seal across a broad range of older Nissan and Tohatsu outboard gearcase applications.

Supplied application data includes Nissan engines from approximately 2 HP through 140 HP across various 1996-2008 applications, including 2.5, 3.5, 4, 5, 6, 8, 9.8, 9.9, 15, 18, 20, 25, 30, 35, 40, 50, 60, 70, 90, 115, 120 and 140 HP listings.

The supplied data also specifically includes a 1996 Tohatsu 90 HP application.

Pro Marine Aftermarket Version Available

Pro Marine Drain Plug Seal - 9522P

Looking for an aftermarket alternative? Pro Marine also stocks the 9522P drain plug seal for customers who do not require the genuine Mercury-branded part.

This gives dealers, service shops and boat owners a choice between OEM Mercury 8M0082880 and the Pro Marine aftermarket 9522P.

View Pro Marine 9522P Drain Plug Seal

OEM Mercury or Pro Marine?

Replace the Seal When Servicing Gear Lube

Mercury recommends replacing the seal when changing gear lubricant or whenever the existing seal shows signs of wear or damage.

During lower-unit service:

1. Remove the applicable gearcase drain/fill screw.
2. Remove and inspect the existing seal.
3. Drain and refill the gearcase according to the engine manufacturer's procedure.
4. Install the correct drain-plug seal.
5. Reinstall and tighten the screw according to the manufacturer's specification.
6. Inspect the area for leakage after service.

Why the Lower Unit Drain Plug Seal Matters

Outboard gearcases operate submerged in water. The drain and fill screws therefore need reliable seals.

A damaged or incorrectly installed seal can compromise the sealing point around the screw. Water contamination can reduce the lubricating ability of the gear oil and may contribute to internal gearcase damage.

If drained gear lube appears unusually milky or shows other signs of water contamination, the gearcase should be inspected rather than simply refilled and returned to service.

Key Features and Benefits

• Genuine Mercury Marine OEM part
• Manufacturer item number 8M0082880
• Gearcase drain plug seal / washer
• Blue seal/washer
• Helps keep gear lubricant inside the lower unit
• Helps prevent water intrusion at the applicable drain screw
• Used on select Mercury and Mariner outboards
• Cross-references to select Johnson, Evinrude, Nissan and Tohatsu applications
• Multiple OEM and aftermarket cross-reference numbers
• Pro Marine 9522P aftermarket alternative available

FAQ

What is Mercury 8M0082880?
It is an OEM Mercury Marine gearcase drain plug seal / washer used on select outboard lower units.

What does the drain plug seal do?
It seals the applicable gearcase drain/fill screw to help keep gear lube inside the lower unit and water outside.

Should I replace the drain plug seal when changing gear lube?
Mercury recommends replacing the seal during gear-lube changes or when the existing seal shows signs of wear or damage.

Does 8M0082880 replace 95220?
Yes. 95220 is one of the listed cross-reference / superseded numbers associated with 8M0082880.

Does 8M0082880 replace 8M0075255?
Yes. 8M0075255 is listed as a cross reference for Mercury 8M0082880.

Does it cross to Sierra 18-60103?
Cross-reference data associates 18-60103 with this drain-plug seal application.

Does this fit Johnson and Evinrude outboards?
Cross-reference data includes numerous Johnson and Evinrude 3-15 HP four-stroke model-number applications. Verify the complete engine model number before ordering.

Does this fit Nissan and Tohatsu outboards?
Cross-reference data includes numerous Nissan and Tohatsu applications. Because the supplied application list spans multiple horsepower ranges, years and gearcase designs, verify the exact model and original part number before ordering.

Is there an aftermarket version?
Yes. Pro Marine stocks the 9522P Pro Marine Drain Plug Seal as an aftermarket alternative.

Is 8M0082880 OEM?
Yes. This listing is for the genuine Mercury Marine OEM version.

Searchable Part Numbers

8M0082880, 8M0075255, 8M0188617, 898101080, 95220, 95220010, 18-60103, 18-72656, 332600060, 332600060M, 332600061, 332600061M, 5040030, 9522P

Searchable Terms

Mercury drain plug seal, Mercury lower unit drain washer, Mercury gearcase drain seal, Mercury drain screw gasket, Mercury gear lube drain washer, Johnson drain plug seal, Evinrude drain plug seal, Tohatsu drain plug washer, Nissan outboard drain plug seal, lower unit drain screw seal, outboard gearcase washer

Common Compatible Applications

OEM Part Numbers & Cross References

What This Drain Plug Seal is Used For

The Mercury 8M0204693 seal washer is used during lower unit and sterndrive gear lube service to help seal drain screws and vent screws against lubricant leaks.

Replacing the seal washer during gear lube service helps maintain proper sealing pressure and helps reduce the risk of water intrusion into the gearcase.

Mercury recommends replacing drain plug seals during routine lower unit service and gear lube changes.

Key Features and Benefits

• Genuine OEM Mercury drain plug seal washer
• Replaces Mercury part number 830749
• Fits many Mercury outboards and MerCruiser sterndrives
• Fits Verado, Pro XS, Racing, FourStroke, and Optimax applications
• Fits many SportMaster and TorqueMaster gearcases
• Commonly used during lower unit gear lube service
• Helps prevent gear lube leaks and water intrusion
• Used on drain screws, vent screws, and fill plugs
• Designed for harsh marine environments

Part Details

• Part Number: 8M0204693
• Supersedes: 830749
• Product Type: Drain Plug Seal Washer
• Brand: Mercury Marine
• Application: Mercury Outboards & MerCruiser Drives
• Use Location: Lower Unit Drain, Fill & Vent Screws
• OEM Mercury Part: Yes

FAQ

What does Mercury 8M0204693 replace?
This drain plug seal replaces Mercury part number 830749.

What is this seal used for?
It seals lower unit drain screws, vent screws, and gear lube fill plugs on Mercury outboards and MerCruiser sterndrives.

Does this fit Mercury Racing lower units?
Yes. This seal is commonly used on Mercury Racing SportMaster, TorqueMaster, and HD lower units including 300R, 450R, and 500R applications.

Does this fit MerCruiser sterndrives?
Yes. This seal is used on many Alpha, Bravo, Blackhawk, NXT, Zeus, and M-Series sterndrives.

Should drain plug seals be replaced during service?
Yes. Mercury recommends replacing drain plug seals during routine gear lube service to help prevent leaks and water intrusion.

Is this a genuine Mercury part?
Yes. This is a genuine OEM Mercury Marine drain plug sealing washer.

Searchable Terms

8M0204693, 830749, Mercury drain plug seal, Mercury drain screw washer, Mercury gearcase washer, Mercury lower unit seal, Mercury gear lube washer, Mercury vent screw seal, Mercury drain plug gasket, Verado drain plug seal, Mercury Pro XS drain seal, Mercury Racing drain washer, Mercury 500R drain plug seal, Mercury 450R drain plug washer, SportMaster drain plug seal, TorqueMaster washer, Mercury Bravo drain washer, Mercury Alpha drain washer, MerCruiser drain plug seal, MerCruiser Bravo washer, MerCruiser Alpha washer, Mercury gearcase drain seal, Mercury lower unit washer, Mercury fill screw seal, Mercury OEM washer

OEM and Cross Reference Numbers

Pro Marine 9522P is used as an aftermarket replacement for applications associated with the following OEM and cross-reference numbers:

Several of these numbers are documented as interchangeable drain-plug seal references across Mercury and Tohatsu applications. Always verify the original part number and engine model before ordering.

What This Part is Used For

The 9522P drain plug seal fits around the applicable gearcase drain or fill screw. When the screw is tightened, the seal helps create a barrier between the lower unit and the surrounding water.

A properly sealing drain screw helps:

• Keep lower-unit gear lubricant inside the gearcase
• Help prevent water intrusion around the drain screw
• Restore the sealing surface during routine gear-lube service
• Reduce the chance of gear-lube leakage at the screw

Mercury and Mariner Fitment

This aftermarket seal corresponds to applications using Mercury OEM 8M0082880 and related cross-reference numbers. Pro Marine currently lists the OEM version in the Mercury lower-unit drain plug and washer category for select small-outboard applications. :contentReference[oaicite:0]{index=0}

Johnson and Evinrude Fitment

Cross-reference data supplied for this application includes numerous Johnson and Evinrude 3-15 HP four-stroke model families. Verify the complete model number, including the suffix, before ordering.

Tohatsu and Nissan Outboard Fitment

The 9522P also corresponds to Tohatsu and Nissan drain-plug seal applications associated with the 332-60006-0 / 332-60006-1 family of part numbers. Independent cross-reference sources also associate those Tohatsu numbers with Mercury 8M0082880 and 95220. :contentReference[oaicite:1]{index=1}

Nissan / Tohatsu Parts Diagram Applications

The supplied application data shows this seal appearing in multiple assemblies and parts diagrams, including:

• Assembly Kit / Assembly Kits
• Bar Handle
• Bracket Reverse Lock
• Carburetor
• Cylinder Crank Case Assembly
• Cylinder Crankcase Assembly
• Cylinder Crankcase and Reed Valve
• Cylinder Head
• Drive Housing / Gear Case
• Drive Shaft Housing
• Drive Shaft Housing / Gear Case
• Drive Shaft Housing / Gear Case / Steering Handle
• Electric Starter
• Fuel Pump
• Fuel Tank Remote
• Gear Case
• Gear Case / Drive Shaft
• Gear Shift
• Inlet / Reed Valve
• Magneto
• Motor Cover
• Piston / Crank Shaft
• Recoil Starter
• Remote Control
• Starter Lock
• Throttle Mechanism
• Transmission / Water Pump

Genuine Mercury OEM Version Available

Mercury OEM Drain Plug Seal - 8M0082880

Prefer the genuine Mercury-branded component? Pro Marine also stocks Mercury OEM 8M0082880.

Both listings give customers a choice between the OEM Mercury part and the Pro Marine aftermarket replacement.

View Mercury OEM 8M0082880

Pro Marine or OEM Mercury?

Gear-Lube Service Tips

• Inspect the drain and fill screw seals whenever the lower-unit oil is changed.
• Replace seals that are damaged, distorted, hardened or questionable.
• Clean the drain screw and sealing surface before reassembly.
• Use the correct gear lubricant for the engine and gearcase.
• Install and tighten the drain/fill screws according to the manufacturer's procedure.
• Inspect for leakage after service.
• If the drained lubricant appears milky, investigate possible water intrusion before returning the engine to service.

Key Features and Benefits

• Pro Marine aftermarket drain plug seal
• Part number 9522P
• Replacement option for Mercury 8M0082880 applications
• Cross-references Mercury 95220 and 8M0075255 applications
• Cross-references Tohatsu 332600060 / 332600061 applications
• Used on select Mercury and Mariner lower units
• Application data includes select Johnson and Evinrude models
• Application data includes select Nissan and Tohatsu models
• Helps seal the applicable lower-unit drain/fill screw
• OEM Mercury version also available

FAQ

What is Pro Marine 9522P?
It is an aftermarket lower-unit drain plug seal / washer for select outboard applications.

Does 9522P replace Mercury 8M0082880?
This Pro Marine version is offered as the aftermarket alternative for applications using Mercury 8M0082880 and its associated cross references.

Does it replace Mercury 95220?
Yes. 95220 is part of the cross-reference family associated with 8M0082880. :contentReference[oaicite:2]{index=2}

Does it cross to Tohatsu 332600060?
Cross-reference sources associate Tohatsu 332-60006-0 / 332600060 and 332-60006-1 / 332600061 with Mercury 8M0082880 and 95220 applications. :contentReference[oaicite:3]{index=3}

Does this fit Johnson and Evinrude?
The supplied fitment data includes numerous Johnson and Evinrude four-stroke model families from 3-15 HP. Verify the complete model number before ordering.

Does this fit Nissan and Tohatsu?
Yes, the supplied fitment data includes numerous Nissan applications and a specifically listed 1996 Tohatsu 90 HP application. Verify the exact engine model and original part number because not every engine within a listed horsepower range uses the same seal.

Do you stock the genuine Mercury version?
Yes. Pro Marine also stocks Mercury OEM 8M0082880 .

Searchable Part Numbers

9522P, 8M0082880, 8M0075255, 8M0188617, 898101080, 95220, 95220010, 18-60103, 18-72656, 332600060, 332600060M, 332600061, 332600061M, 5040030

Searchable Terms

Pro Marine drain plug seal, Mercury drain plug seal aftermarket, Mercury lower unit drain washer, Tohatsu drain plug gasket, Nissan drain plug seal, Johnson drain plug seal, Evinrude drain plug washer, gearcase drain screw seal, lower unit drain gasket, gear lube drain plug washer