Fuel Filter Kit – Fits MerCruiser 2.5L, 3.0L, 3.7L, 4.3L Sterndrive Engines (Replaces 803897Q1, 8M0046752)

Fuel Filter Kit – Fits MerCruiser 2.5L, 3.0L, 3.7L, 4.3L Sterndrive Engines

This fuel filter kit is designed for a range of MerCruiser 2.5L, 3.0L, 3.7L, and 4.3L 4-stroke sterndrive engines, covering specific models manufactured from the 1980s through the 2000s. It is compatible with engines equipped with a mechanical fuel pump mounted on the engine block.

This kit is a direct replacement for multiple OEM and aftermarket part numbers, including MerCruiser 35-803897Q1, 8M0046752, 803897K1; Sierra 18-7784; Mallory 9-37821; and Volvo Penta 3855104.

• Fuel Type: Designed for gasoline-powered engines.
• Installation Location: Fits inside the lower canister of the engine-mounted mechanical fuel pump.
• Complete Kit: Includes the filter element, spring, and all necessary rubber gaskets and rings for a full replacement.

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.

Technical Specifications

Package Contents

• 1x Filter Element
• 1x Spring
• 3x Rubber Rings/Gaskets

Installation Guide

1. Ensure the engine is off, cool to the touch, and the battery is disconnected for safety.
2. Locate the mechanical fuel pump, typically mounted on the side of the engine block. Place a rag underneath to catch fuel spillage.
3. Carefully unscrew and remove the pump's lower canister. Be prepared for some residual fuel to drain out.
4. Take out the old filter, spring, and any gaskets/rings inside, noting their order and orientation.
5. Clean any debris from the inside of the pump canister before installing the new components.
6. Insert the new spring, filter element, and rubber gaskets from the kit in the correct order.
7. Securely re-attach and tighten the fuel pump canister. Do not overtighten.
8. Reconnect the battery, prime the fuel system according to your engine's manual, and carefully check for leaks.

Troubleshooting & FAQ

Q: How do I know if this filter kit fits my MerCruiser engine?

A: First, confirm your engine is a 2.5L, 3.0L, 3.7L, or 4.3L model with a mechanical (not electric) fuel pump. Cross-reference your engine's serial number with the ranges listed in the compatibility table and ensure your existing part number matches one from our cross-reference list.

Q: What are the signs of a clogged fuel filter?

A: Common symptoms include the engine struggling to start, stalling at low speeds, rough idling, misfiring, or a noticeable loss of power, especially when accelerating or under load.

Q: How often should I replace this fuel filter?

A: For best performance and to protect your fuel system, we recommend replacing the fuel filter at least once per season or every 100 hours of operation, whichever comes first.

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.