Bypass Cover Gasket – Fits Johnson/Evinrude Outboards (Replaces 307133)

$14.99 $23.00

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Product Details

This bypass cover gasket provides a reliable seal for the bypass cover assembly on a wide range of Johnson/Evinrude outboard engines, including 9.9 to 300 HP models across both 2-stroke and 4-stroke generations. Proper sealing is essential to prevent coolant or exhaust leaks, ensuring optimal engine performance and longevity.

It serves as a direct replacement for Johnson/Evinrude OEM part number 307133.

Engineered for direct-fit installation.
Resistant to heat, oil, and coolant for durable performance.
Sold in a convenient value pack of five gaskets.

Part Number Matrix

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

Brand	Part Number
Johnson/Evinrude	307133

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Brand	Model	Rated HP	Stroke	OEM Part No.	Notes
Johnson/Evinrude	Outboard engines	9.9–300	2-Stroke & 4-Stroke	307133	Specific model compatibility information needed

Technical Specs

Product Type: Bypass Cover Gasket
Installation: Direct replacement
Housing Material: Gasket material (likely paper/composite)
Dimensions: 6.0" H x 7.5" W x 1.25" L
Warranty: 90-Day Warranty (per retailer)
Other Technical Attributes: Sold in a pack of 5 gaskets

What’s in the Box

5 x Bypass Cover Gasket (307133)

Installation Notes

Ensure the engine is off and cool, and disconnect the battery for safety.
Locate and carefully remove the engine's bypass cover assembly.
Thoroughly clean both the cover and the engine block mating surfaces. Ensure all old gasket material, sealant, and debris are completely removed.
Position the new gasket onto the engine block, aligning it with the bolt holes.
Reinstall the bypass cover and tighten the bolts in a crisscross pattern to the manufacturer's specified torque.
Reconnect the battery, start the engine, and carefully inspect for any leaks around the cover.

Troubleshooting & FAQ

How do I know if my bypass cover gasket is failing?

Signs of a failing bypass cover gasket include visible coolant or water leaks around the cover area, engine overheating, or a rough-running engine. A visual inspection may reveal cracking or degradation of the gasket material.

Can I reuse the old gasket?

No. Gaskets are single-use components designed to compress and create a seal. Once removed, they lose their sealing ability and must be replaced to prevent leaks.

Is any sealant required with this gasket?

Generally, this type of gasket is designed to be installed dry. However, always consult your engine's specific service manual for any manufacturer recommendations regarding the use of sealants.

What is the function of the bypass cover?

The bypass cover typically seals a passage in the cooling system, allowing coolant to circulate properly within the engine block for temperature regulation. A proper seal is critical for preventing overheating.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9001 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

Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
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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