Fuel Connector Cap – Fits Mercury 4–30 HP (Replaces 878311)

Fuel Connector Cap – Fits Mercury 4–30 HP (Replaces 878311)

This cap seals the fuel connection on integral fuel tanks for various Mercury outboard engines. It is designed for Mercury models from 4 HP to 30 HP, primarily 4-stroke engines, providing a secure fit to prevent fuel leaks and contamination.

This part is a direct replacement for Mercury 878311, Suzuki 65727-91JL0, Tohatsu 3H6-70262-0, and QuickSilver 878311.

• Installation Method: Simple screw-on design
• Housing Material: Durable black rubber construction
• Application: Designed for use with integral (built-in) fuel tanks

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

For Suzuki owners, You can review exploded diagrams here to verify part numbers: Suzuki Parts Diagrams & Catalog.

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

Includes:

• 1 x Cap (878311)

Installation Guide

1. Safety First: Ensure the engine is completely off and cool to the touch.
2. Locate Inlet: Identify the fuel inlet connection on the outboard's integral fuel tank.
3. Clean Area: Wipe the area around the inlet clean to prevent debris from entering the fuel system.
4. Remove Old Cap: Unscrew the old or damaged cap.
5. Install New Cap: Align the new cap with the threads on the fuel inlet and screw it on by hand.
6. Secure Firmly: Tighten until snug to create a proper seal. Do not overtighten, as this can damage the rubber or the tank threads.

Troubleshooting & FAQ

Q: How do I confirm this cap fits my engine?

A: This cap fits a wide range of Mercury 4-stroke outboards from 4 HP to 30 HP that use an integral fuel tank. The best way to confirm is by matching your old part number to the ones listed in our cross-reference table: Mercury 878311, Suzuki 65727-91JL0, or Tohatsu 3H6-70262-0.

Q: What are the signs that my fuel connector cap needs replacing?

A: Common signs include visible cracks or brittleness in the rubber, a loose fit that won't tighten properly, or the smell of fuel fumes around the tank, indicating a poor seal.

Q: Is this rubber cap resistant to ethanol-blended fuels?

A: Yes, it is made from modern rubber compounds designed to be resistant to gasoline and common ethanol blends, preventing premature swelling or deterioration.

Q: OEM vs. Aftermarket?

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?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.