Tilt Clutch Cover Gasket – Fits OMC Sterndrive & Johnson/Evinrude Outboards (Replaces 308799)

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Product Details

This is a replacement Tilt Clutch Cover Gasket designed for a range of OMC Sterndrive systems, including Cobra and Stringer models. It is also compatible with select Johnson and Evinrude outboard engines that utilize the same gasket for the tilt clutch cover assembly, ensuring a proper seal to prevent fluid leaks.

This part is a direct interchange for OEM part number 308799 / 0308799 and aftermarket equivalent Sierra 18-2863.

Designed for direct replacement of the original factory gasket.
Engineered to seal the tilt clutch cover assembly effectively.
Package includes one cover gasket.

Part Number Matrix

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

Brand	Part Number
OMC	308799
OMC	0308799
Sierra	18-2863

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This gasket is known to fit various OMC Cobra and Stringer sterndrives. Please verify your specific model requirements.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
OMC	Cobra Sterndrive	Various	Various		308799	Tilt clutch cover gasket
OMC	Stringer Sterndrive	Various	Various		308799	Tilt clutch cover gasket

Also used on select Johnson/Evinrude outboards. Compatibility can vary widely, so always check your service manual.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Johnson/Evinrude	Various				308799	Cover gasket

Technical Specs

Product Type: Tilt Clutch Cover Gasket
Installation: Direct replacement
Housing Material: Gasket material (likely composite/paper)
Dimensions: 18.0" L x 14.0" W x 0.5" H
Other Technical Attributes: Factory OEM gasket for tilt clutch cover

What’s in the Box

1 x Cover Gasket (308799/0308799)

Installation Notes

Disconnect the battery to prevent accidental operation of the trim/tilt system.
Access the tilt clutch assembly on your sterndrive or outboard. This may require removing other components.
Carefully remove the bolts securing the tilt clutch cover.
Remove the old cover and gasket. Take note of the orientation of all parts.
Thoroughly clean both the cover and the housing mating surfaces. Ensure they are free of old gasket material, sealant, and debris.
Position the new gasket correctly on the housing.
Reinstall the cover and tighten the bolts to the manufacturer's specified torque in a crossing pattern.
Reconnect the battery and test the tilt/trim system for proper operation and any signs of leaks.

Troubleshooting & FAQ

How do I know if this gasket fits my specific engine model?

The best way to confirm is by matching your existing part number to OMC 308799, 0308799, or Sierra 18-2863. While this gasket fits many OMC sterndrives and select Johnson/Evinrude outboards, always consult your engine's service manual for definitive compatibility.

What are the signs of a failing tilt clutch cover gasket?

The most common sign is a hydraulic fluid leak around the tilt clutch cover. You may also notice a whining noise from the trim/tilt pump as it struggles with low fluid levels, or the drive may not hold its position properly.

Do I need to use sealant with this gasket?

Generally, new gaskets are designed to be installed dry. However, always refer to your specific engine's service manual. Some applications may recommend a light coating of a specific sealant or grease.

What is the difference between this aftermarket gasket and an OEM one?

This aftermarket gasket is manufactured to meet or exceed original equipment manufacturer (OEM) specifications for fit, form, and function. It provides a cost-effective solution without compromising on quality or sealing performance, using comparable materials.

Can I replace this gasket myself?

Yes, replacement is feasible for individuals with mechanical experience and the correct tools. However, due to the importance of a proper seal and the need to follow torque specifications, professional installation is recommended to ensure safety and prevent leaks.

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 a 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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Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

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