Cylinder Head Gasket for Johnson Evinrude 40-60 HP Outboards – Replaces 327795, 335359
This aftermarket cylinder head gasket is engineered for Johnson and Evinrude 2-cylinder outboard engines rated 40–60 HP. Designed to restore a reliable seal between the cylinder head and block, it ensures optimal compression and prevents coolant or combustion gas leaks in your outboard motor.
This gasket directly replaces OEM part numbers 320658, 327795, 335359, 878850, 0777395, and 0335359, as well as aftermarket equivalents from Sierra (18-3802), GLM (34250), and Mallory (9-63833), offering broad cross-compatibility for easy sourcing and installation.
- Precision-cut design ensures proper fitment on Johnson/Evinrude 2-cylinder powerheads
- Durable material withstands high temperatures and pressures in marine environments
- Cost-effective alternative to OEM gaskets without compromising sealing performance
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Johnson/Evinrude (OEM) |
320658 |
| Johnson/Evinrude (OEM) |
327795 |
| Johnson/Evinrude (OEM) |
335359 |
| Johnson/Evinrude (OEM) |
878850 |
| Johnson/Evinrude (OEM) |
0777395 |
| Johnson/Evinrude (OEM) |
0335359 |
| Sierra |
18-3802 |
| GLM |
34250 |
| Mallory |
9-63833 |
Compatible Engine Models
Confirm your engine model/year in the table below. For Johnson/Evinrude owners, here's a guide to help you identify your engine's serial/model: Johnson/Evinrude Serial Number Guide.
| Brand |
Model |
Rated HP |
| Johnson/Evinrude |
2-Cylinder Outboards |
40–60 HP |
Technical Specifications
| Specification |
Value |
| Product Type |
Cylinder Head Gasket |
| Application |
Johnson/Evinrude 2-Cylinder Outboards 40–60 HP |
| OEM Reference Numbers |
320658, 327795, 335359, 878850, 0777395, 0335359 |
| Aftermarket Cross-Reference |
Sierra 18-3802, GLM 34250, Mallory 9-63833 |
Package Contents
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1 × Cylinder Head Gasket for Johnson/Evinrude 40–60 HP
Installation Guide
- Disconnect the battery and allow the engine to cool completely before beginning work.
- Remove the engine cover and locate the cylinder head assembly on your outboard.
- Disconnect the spark plug wires and any hoses or cables attached to the cylinder head.
- Remove the cylinder head bolts in a crisscross pattern, starting from the outside and working inward.
- Carefully lift the cylinder head off the engine block and set it aside on a clean surface.
- Thoroughly clean all gasket material residue from both the cylinder head and block mating surfaces using a gasket scraper and solvent.
- Inspect the cylinder head and block for cracks, warping, or damage; resurface or replace components if necessary.
- Position the new cylinder head gasket onto the block, aligning all bolt holes and coolant passages precisely.
- Reinstall the cylinder head, ensuring proper alignment with the dowel pins (if equipped).
- Hand-tighten all cylinder head bolts, then torque them to manufacturer specifications in a crisscross pattern, working from the center outward.
- Reconnect all hoses, cables, and spark plug wires in the reverse order of removal.
- Reconnect the battery, start the engine, and check for leaks or unusual noises; allow the engine to warm up and verify proper operation.
Troubleshooting & FAQ
Q: How do I confirm this gasket fits my Johnson or Evinrude outboard?
A: Verify your engine is a 2-cylinder model rated 40–60 HP, and cross-check your original gasket or parts diagram against the OEM numbers listed (320658, 327795, 335359, etc.). If your part number matches, this gasket will fit.
Q: What are the signs that my cylinder head gasket needs replacement?
A: Common symptoms include coolant leaks around the cylinder head, white smoke from the exhaust, overheating, loss of compression, rough idling, or visible gasket material deterioration during inspection.
Q: How often should I replace the cylinder head gasket?
A: Replace the gasket whenever the cylinder head is removed for service, or immediately if you notice leaks, overheating, or compression loss. Regular maintenance intervals vary, but inspect the gasket annually or every 100 hours of operation.
Q: Can I reuse the old gasket if it looks intact?
A: No, cylinder head gaskets are designed for one-time use. Reusing an old gasket—even if it appears undamaged—can result in improper sealing, leaks, and engine damage.
Q: What is the difference between this aftermarket gasket and the OEM version?
A: This aftermarket gasket is manufactured to OEM specifications using comparable-grade materials in an ISO9002-certified facility. It delivers equivalent sealing performance and fitment at a more competitive price point than OEM parts.
Q: Do I need to apply sealant to the gasket during installation?
A: Generally, no additional sealant is required if the mating surfaces are clean and flat, and the gasket is installed dry. Consult your engine's service manual for specific instructions, as some applications may recommend a light coating of sealant.
Q: Is this an OEM or aftermarket part?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.