Fuel Injector – Fits Mercruiser 8.1L/496 MAG/496 HO MPI Engines (Replaces 881693002, 3861278)

Fuel Injector – Fits Mercruiser 8.1L/496 MAG/496 HO MPI Engines

This multi-port fuel injector is designed for Mercruiser 8.1L/496 cubic inch engines (including 8.1S MPI, 8.1L HO, 496 MAG, and 496 HO models) from 2004 and later equipped with Multi-Port Injection (MPI) systems. It serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 881693002, 881693001, and 3861278. The injector features a metal housing and a 3-hole disc nozzle based on the Delphi design, connecting via a standard Delphi Multec II electrical interface.

• Installation Method: Direct OEM replacement
• Fuel Compatibility: Gasoline
• Included Components: 1 x Fuel Injector with pre-installed O-rings

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

• 1 x Fuel Injector (Replaces 881693002/3861278/25348180)

Installation Guide

1. Relieve Fuel Pressure: Safely relieve the pressure from the fuel system according to the manufacturer's service manual.
2. Disconnect Battery: Disconnect the negative terminal of the battery.
3. Disconnect Injector: Unplug the electrical connector and carefully disconnect the fuel line from the injector.
4. Remove Retainer: Remove the retaining clip or bolts holding the fuel injector in place.
5. Extract Old Injector: Gently twist and pull to remove the old injector from the fuel rail. Be prepared for minor fuel spillage.
6. Lubricate O-Rings: Apply a small amount of clean engine oil to the new O-rings on the replacement injector.
7. Install New Injector: Press the new injector firmly into the fuel rail until it seats correctly.
8. Secure Injector: Reinstall the retaining clip or bolts to secure the injector.
9. Reconnect Lines: Re-attach the fuel line and plug in the electrical connector.
10. Reconnect Battery: Reconnect the negative battery terminal.
11. Check for Leaks: Prime the fuel system by turning the key to the "On" position a few times, then check thoroughly for any fuel leaks around the injector before starting the engine.

Troubleshooting & FAQ

Q: How do I know if this fuel injector fits my 496 engine?
A: This injector fits MerCruiser 8.1L/496 MAG and HO MPI models from 2004 and later. Verify your engine model against the "Compatible Engine Models" table and cross-reference your existing part number with the numbers listed, such as 881693002 or 3861278.

Q: What are the signs of a failing fuel injector?
A: Common symptoms include engine misfires, rough idling, poor acceleration, increased fuel consumption, or difficulty starting. A fuel smell may also be present if the injector is leaking.

Q: Are these injectors the same as the original Delphi parts?
A: These are aftermarket injectors built to meet or exceed OEM specifications. They feature the same Delphi Multec II electrical connection and 3-hole nozzle design for compatible performance.

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.