Head Gasket and Water Jacket Cover Gasket Set for Johnson/Evinrude 90° V4 Crossflow Outboards
Head Gasket and Water Jacket Cover Gasket Set for Johnson/Evinrude 90° V4 Crossflow Outboards is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Head Gasket and Water Jacket Cover Gasket Set for Johnson/Evinrude ...
Head Gasket and Water Jacket Cover Gasket Set for Johnson/Evinrude 90° V4 Crossflow Outboards is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Head Gasket and Water Jacket Cover Gasket Set is intended for selected Johnson/Evinrude 90° V4 crossflow outboard applications. The set combines the cylinder-head gasket with the gasket for the powerhead water-jacket cover, helping restore sealing at both service locations during a compatible engine repair.
The included gasket references correspond to Johnson/Evinrude/OMC numbers 318358 and 318335. Catalog cross-references identify 318358 with V4 90° crossflow head-gasket applications and 318335 with a V4 powerhead water-passage cover gasket. Always compare the engine model, year, serial number, gasket shape, bolt pattern, and original part before ordering.
- Combination set for one compatible V4 service application.
- Includes one head gasket and one water-jacket cover gasket.
- Designed for selected Johnson/Evinrude 90° V4 crossflow outboards.
- Aftermarket replacement; not an OEM-manufactured part.
Part Number Matrix
These are manufacturer and aftermarket reference numbers associated with the two gasket types in this set. They are provided for identification and interchange research only; verify the complete application before purchase.
| Gasket | OEM / OMC Reference | Aftermarket Reference |
|---|---|---|
| Head gasket | 318358 | Sierra 18-2956; GLM 33540 |
| Water-jacket cover gasket | 318335 | Sierra 18-2873; GLM 33530 |
Engine Compatibility
This set is intended for selected Johnson/Evinrude 90° V4 crossflow, 2-stroke outboards using the head-gasket and water-jacket-cover references listed above. Catalog material associates reference 318358 with V4 90° crossflow applications, including examples in the 1973–1994 range, while the water-jacket-cover reference 318335 is listed for V4 applications. These references are not sufficient by themselves to confirm every model, year, horsepower rating, or serial-number range.
| Engine family | Stroke | Application guidance | Verification required |
|---|---|---|---|
| Johnson/Evinrude 90° V4 Crossflow | 2-Stroke | Selected applications using head-gasket reference 318358 and water-jacket-cover reference 318335 | Confirm exact model, year, serial number, gasket profile, and bolt pattern |
Technical Specifications
- Product Type
- Head gasket and water-jacket cover gasket set
- Engine Family
- Selected Johnson/Evinrude 90° V4 crossflow outboards
- Engine Type
- 2-stroke outboard
- Installation
- Position-specific; install each gasket only in its matching location
- Package Contents
- 1 x head gasket and 1 x water-jacket cover gasket
- Head Gasket Reference
- Replaces or cross-references Johnson/Evinrude 318358
- Water-Jacket Cover Gasket Reference
- Replaces or cross-references Johnson/Evinrude 318335
- Construction
- Aftermarket gasket materials; exact material composition and finish may vary by production batch
What’s in the Box
- 1 x Head Gasket — reference 318358
- 1 x Water-Jacket Cover Gasket — reference 318335
- This set is for the listed compatible gasket locations; it does not include cylinder-head bolts, sealant, thermostat parts, or other engine gaskets.
Installation Notes
- Confirm the exact engine model, year, serial number, gasket shape, and service-manual specifications before disassembly.
- Disconnect the battery and remove or secure fuel sources in accordance with the engine manufacturer's safety procedures.
- Remove the engine-cover components and other parts that obstruct access to the cylinder head and water-jacket cover.
- Remove the water-jacket cover and cylinder head carefully. Keep bolts and components organized by location.
- Clean the mating surfaces thoroughly without gouging the cylinder head, block, or cover. Remove old gasket material, oil, and debris.
- Place the new head gasket in the correct orientation. Do not apply sealant unless the manufacturer's service manual specifically requires it.
- Reinstall the cylinder head and tighten the fasteners in the specified sequence and stages using the manufacturer's torque values.
- Install the new water-jacket cover gasket and reinstall the cover using the specified torque and tightening sequence.
- Reconnect removed components and carry out the manufacturer's cooling-system and fuel-system checks.
- Run the engine using the approved test procedure and inspect for water leaks, combustion-gas leakage, overheating, or abnormal compression.
Troubleshooting & FAQ
What engine does this gasket set fit?
It is intended for selected Johnson/Evinrude 90° V4 crossflow 2-stroke outboards that use head-gasket reference 318358 and water-jacket-cover gasket reference 318335. Exact model, year, and serial-number verification is required.
Does this set fit every Johnson/Evinrude V4?
No. Johnson/Evinrude used multiple V4 designs, including crossflow and loopcharged versions with different gasket applications. Do not use horsepower alone to confirm fitment. Compare the complete engine identification and the original gasket before ordering.
What parts are included?
The set includes one head gasket and one water-jacket cover gasket. It does not include a full engine overhaul gasket set, head bolts, thermostat gaskets, bypass-cover gaskets, or sealant.
What are the aftermarket reference numbers?
The head gasket is cross-referenced with Sierra 18-2956 and GLM 33540. The water-jacket cover gasket is cross-referenced with Sierra 18-2873 and GLM 33530. These references should be checked against the exact application rather than used as a substitute for model and serial-number verification.
Do I need gasket sealant?
Do not apply sealant unless the official service manual specifically calls for it. Incorrect sealant use can affect gasket seating, cooling passages, or torque readings.
What are common signs of a failed head gasket?
Possible symptoms include overheating, loss of compression, poor running, combustion gases entering the cooling passages, water leakage, or an inability to maintain the correct cooling-water flow. Diagnose the engine before replacing parts.
Is this an OEM part?
No. This listing is for an aftermarket replacement set. The OEM and aftermarket numbers shown are reference numbers used to help identify the application.
Safety & Important Information
- Verify the exact model, year, serial number, stroke, engine architecture, and original gasket profile before ordering.
- Do not rely on horsepower or a single part number when confirming fitment.
- Use the manufacturer's service manual for disassembly, torque values, tightening sequence, sealant requirements, and testing procedures.
- Professional installation is recommended for cylinder-head and powerhead gasket work.
About Sea Sierra
- Marine Replacement Parts — We provide aftermarket parts for maintenance and repair applications.
- Application-Focused Listings — Reference numbers and compatibility guidance are provided to support careful part identification.
- Customer Support — Compare your engine identification and original part details before ordering or contact support with the complete application information.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
