Fuel Pump Gasket – Fits Johnson/Evinrude Outboards (Replaces OMC 338879)

$6.88 $11.00

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Product Details

This high-quality aftermarket Fuel Pump Gasket – Fits Johnson/Evinrude Outboards (Replaces OMC 338879) ensures a reliable seal between the fuel pump cap and the pump body. It is designed for a wide range of Johnson, Evinrude, and OMC outboard engines manufactured across various years, typically from the 1970s through the 2000s.

This part serves as a direct replacement for OMC part numbers 338879 and 0338879, as well as Sierra interchange part numbers 18-0965 and 18-2900.

Installs between the upper fuel pump cap and body.
Made from durable, fuel-resistant rubber compound.
Engineered to seal the fuel system and prevent leaks.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number	Notes
OMC	338879	Original Equipment Manufacturer part number.
OMC	0338879	Alternative OEM part number format.
Sierra	18-0965	Aftermarket cross-reference.
Sierra	18-2900	Aftermarket cross-reference.

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Designed for various outboard models from Johnson, Evinrude, and OMC. Always verify your specific part number before ordering.

Brand	Model	Rated HP	Years	Notes
OMC	Various Outboard Models	Various		Fuel pump cap gasket
Johnson/Evinrude	Various Outboard Models	2.5–9.4	1970–2001	Described as cap to fuel pump gasket

Technical Specs

Product Type: Fuel Pump Gasket
Installation: Between fuel pump cap and pump body
Fuel Type: Compatible with gasoline
Housing Material: Rubber compound
Housing Color: Black
Dimensions: 1.25 × 5.13 × 4.0 in
Weight: 0.16 ounces (4.5 g)
Function: Seals upper cap to fuel pump body in OMC/Johnson/Evinrude outboard engines

What’s in the Box

1 x Gasket (Replaces OMC 338879/0338879)

Installation Notes

Disconnect the battery and ensure the engine is cool to the touch. Relieve any pressure from the fuel system according to your service manual.
Locate the fuel pump assembly. Clean the area around it to prevent debris from entering the fuel system.
Carefully remove the screws holding the fuel pump cap in place.
Remove the old gasket and thoroughly clean both mating surfaces (the pump body and the cap). Ensure no old gasket material or sealant remains.
Position the new gasket correctly on the fuel pump body.
Reinstall the cap, ensuring it is properly aligned. Tighten the screws in a star pattern to the manufacturer's recommended torque specifications to ensure an even seal.
Reconnect the battery, prime the fuel system, and check for any leaks before starting the engine.

Troubleshooting & FAQ

How do I know if this gasket will fit my engine?

This gasket fits a broad range of Johnson, Evinrude, and OMC outboards. The best way to confirm compatibility is to match your existing part's number to the ones listed in our Part Number Matrix: OMC 338879/0338879 or Sierra 18-0965/18-2900. Also, check the compatibility table for your engine's HP and year range.

What are the signs of a failing fuel pump gasket?

Common symptoms of a bad gasket include visible fuel leakage around the fuel pump, a strong smell of gasoline, poor engine performance, stalling, or difficulty starting. A failed gasket compromises the fuel system's seal, leading to pressure loss and leaks.

Where is this gasket installed?

This gasket is specifically designed to seal the connection between the upper fuel pump cap and the main fuel pump body.

What is the recommended replacement interval?

There is no fixed replacement interval for this gasket. It should be replaced whenever the fuel pump is serviced or if you notice any signs of leakage or degradation of the old gasket.

Is this a single gasket or a pack?

This listing is for a single gasket, as detailed in the "What’s in the Box" section.

Can I reuse my old gasket or use a sealant?

It is strongly recommended not to reuse an old gasket, as it may be compressed, brittle, or torn, leading to an improper seal. This gasket is designed to be installed dry; do not use any additional liquid gasket or sealant unless explicitly specified by your engine's service manual.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement, not an OEM component.
Professional installation is recommended for safety and performance.

About Sea Sierra

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