Fuel Pump – Fits Tohatsu/Nissan MFS/NSF 4-9.8 HP & Mercury/Mariner 4-6 HP 4-Stroke (Replaces 3H6-04000-7)

Fuel Pump – Fits Tohatsu/Nissan MFS/NSF 4-9.8 HP & Mercury/Mariner 4-6 HP 4-Stroke

This aftermarket fuel pump assembly is designed for a precise fit on a range of Tohatsu, Nissan, Mercury, and Mariner 4-stroke outboard motors. It serves as a direct replacement for engines from 4 HP to 9.8 HP, ensuring reliable fuel delivery and restoring engine performance.

This part replaces multiple OEM part numbers, including Tohatsu/Nissan 3H6-04000-7 and Mercury/Mariner 803529T06. Please verify the part number cross-reference and compatible models list to ensure correct fitment for your specific engine.

• Installation Method: Direct OEM-style replacement.
• Compatible Fuel Type: Gasoline.
• Package Includes: 1 x Fuel Pump Assembly.

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.

Tohatsu/Nissan

Mercury/Mariner

Technical Specifications

Package Contents

• 1 x Fuel Pump Assembly (Replaces 3H6-04000-7)

Installation Guide

1. Safety First: Disconnect the battery and ensure the engine is cool. Work in a well-ventilated area away from open flames or sparks.
2. Relieve Fuel Pressure: Safely relieve the pressure from the fuel system according to your engine's service manual to prevent fuel spray.
3. Disconnect Fuel Lines: Place a rag under the fuel pump to catch any residual fuel. Carefully disconnect the inlet and outlet fuel lines from the pump.
4. Remove Old Pump: Unscrew the mounting bolts holding the fuel pump to the engine block.
5. Install New Pump: Position the new fuel pump and secure it with the mounting bolts, tightening them to the manufacturer's specified torque.
6. Reconnect Fuel Lines: Attach the fuel lines to the new pump, ensuring a secure connection to prevent leaks.
7. Prime and Test: Reconnect the battery. Prime the fuel system by squeezing the primer bulb until firm. Start the engine and carefully inspect for any fuel leaks around the pump and connections.

Troubleshooting & FAQ

Q: How can I confirm this fuel pump fits my specific engine?
A: The best way is to match your original part number to one of the numbers in our "Part Number Cross-Reference" table. Additionally, check your engine's model and year against the "Compatible Engine Models" list. If you're unsure, use the provided guides for Mercury to find your serial number or consult a parts diagram.

Q: What are the common signs of a failing fuel pump?
A: Symptoms of a faulty fuel pump include the engine sputtering or surging, bogging down under acceleration, difficulty starting, or a complete loss of power. These issues occur when the pump can no longer supply the carburetor with a consistent and adequate flow of fuel.

Q: Why are there so many superseded part numbers for this pump?
A: Manufacturers often update part designs over time for improved durability, material changes, or minor functional enhancements. A new part number (e.g., 3H6-04000-7) supersedes the older versions, meaning it is the current and correct replacement for all previous iterations.

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.