Cylinder Head Cover Gasket – Fits Johnson/Evinrude 20-35 HP (Replaces 327674, 324325, 777388)

$8.45 $13.00

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Product Details

This Cylinder Head Cover Gasket is a direct-fit replacement for Johnson/Evinrude 20–35 HP 2-Stroke outboard motors manufactured between 1979 and 2005. It is designed for 2-cylinder engine configurations to prevent oil leaks and ensure a proper seal, maintaining engine integrity and performance.

It serves as a direct interchange for Johnson/Evinrude part numbers 327674, 324325, and 777388, as well as aftermarket equivalents from Sierra, WSM, GLM, and EMP.

Engineered for direct-replacement installation.
Constructed from OEM-specification gasket material for durability and a reliable seal.
Manufactured in an ISO 9002 certified facility to ensure consistent quality.

Part Number Matrix

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

Brand	Part Number
Johnson/Evinrude	327674
Johnson/Evinrude	324325
Johnson/Evinrude	777388
Sierra	18-3899
WSM	505-16
GLM	33700
EMP	27-00939

Engine & Model Compatibility

Confirm your engine model and year in the table below.

For Johnson engines, this gasket fits various 20, 25, 30, and 35 HP models from 1979 to 2005.

For Evinrude engines, this part is compatible with a wide range of 25 and 35 HP models, including specific model series from 1979 to 1981 and general models up to 2005.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.
Johnson	20HP	20	2-Stroke	1985–1997	327674
Johnson/Evinrude	25HP	25	2-Stroke	1979–2005	327674
Johnson/Evinrude	30HP	30	2-Stroke	1985–2004	327674
Johnson/Evinrude	35HP	35	2-Stroke	1979–1994	327674
Evinrude	25904R, 25905R, 25952R, 25953R	25	2-Stroke	1979	327674
Evinrude	E25RCSA, E25RLCSA, E25TECSA, E25TELCSA	25	2-Stroke	1980	327674
Evinrude	E25ECIB, E25ECIM, E25ELCIB, E25ELCIM, E25RCIM, E25RLCIM, E25RSA, E25RSLA, E25RWCIM, E25RWLCIM, E25TECIM, E25TELCIM	25	2-Stroke	1981	327674
Evinrude	35902A, 35903A, 35952A, 35953A	35	2-Stroke	1979	327674
Evinrude	E35ECSM, E35ELCSM, E35TCSM, E35TLESM	35	2-Stroke	1980	327674
Evinrude	E35ECIG, E35ELCG, E35RCIG, E35RLCIG	35	2-Stroke	1981	327674
Johnson	25E79R, 25EL79R, 25R79R, 25RL79R	25	2-Stroke	1979	327674
Johnson	J25RCSA, J25RLCSA, J25TECSA, J25TELCSA	25	2-Stroke	1980	327674
Johnson	J25ECIB, J25ECIM, J25ELCIB, J25ELCIM, J25RCIM, J25RLCIM, J25RSA, J25RSLA, J25RWCIM, J25RWLCIM, J25TECIM, J25TELCIM	25	2-Stroke	1981	327674
Johnson	35E79A, 35EL79A, 35R79A, 35RL79A	35	2-Stroke	1979	327674
Johnson	J35ECSM, J35ELCSM, J35RCSM, J35RLCSM	35	2-Stroke	1980	327674
Johnson	J35ECIG, J35ELCIG, J35RCIG, J35RLCIG	35	2-Stroke	1981	327674

Technical Specs

Product Type: Cylinder Head Cover Gasket
Installation: Direct replacement
Material: OEM-specification gasket material
Production Standards: Manufactured in ISO9002 certified factory
Product Dimensions: 11.25" L x 6.0" W x 1.03" H
Weight: 0.317 ounces (9 grams)
Other Technical Attributes: Designed to prevent oil leaks and maintain engine integrity

What’s in the Box

1 x Cylinder Head Cover Gasket (327674)

Installation Notes

Disconnect the battery and ensure the engine is cool before starting.
Locate and unbolt the cylinder head cover. Note the position of any brackets or components attached to it.
Carefully remove the old gasket. Use a plastic scraper to gently remove any remaining gasket material from both the engine block and the cover.
Clean both mating surfaces thoroughly with a degreaser or appropriate solvent to ensure they are free of oil, dirt, and old gasket residue.
Position the new gasket correctly on the engine block. Ensure all bolt holes align perfectly.
Reinstall the cylinder head cover. Tighten the bolts in the sequence and to the torque specifications recommended by the manufacturer.
Reconnect the battery, start the engine, and carefully inspect for any signs of oil leaks around the cover.

Troubleshooting & FAQ

How do I know if this gasket fits my engine?

The best way to confirm fitment is to check your original part number against the list in our Part Number Matrix. Also, review the comprehensive Engine & Model Compatibility table to ensure your specific engine model and year are listed.

What are the signs of a failing cylinder head cover gasket?

Common signs include visible oil leaks around the cylinder head cover, a smell of burning oil, a dirty or oil-stained engine exterior, and potentially a rough-running engine if oil is leaking onto spark plugs or exhaust components.

Is any special sealant required during installation?

Generally, this gasket is designed to be installed dry. However, always consult your engine's service manual, as some specific models may require a small amount of sealant at sharp corners or joints.

How often should this gasket be replaced?

Replace the gasket whenever the cylinder head cover is removed for service or if you notice any signs of leaking. There is no fixed replacement interval; it is replaced on an as-needed basis.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 facility, with batch inspections for consistency.

Shipping speed & cost

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

Warranty & returns

This product is covered by a 1-year warranty against manufacturing defects under normal use. If any issues arise, contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. See our policy page or reach out for instructions.

Safety & Important Info

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

About Sea Sierra

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Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
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