Fuel Pump – Fits Mercury 4–6 HP & Tohatsu/Nissan 4–9.8 HP 4-Stroke Outboards (Replaces 803529T06, 3H6-04000)

Fuel Pump – Fits Mercury 4–6 HP & Tohatsu/Nissan 4–9.8 HP 4-Stroke Outboards

This fuel pump is a direct replacement for a variety of Mercury, Mariner, Tohatsu, and Nissan 4-stroke outboard engines, covering models from 4 HP to 9.8 HP across various years. It is designed to meet or exceed original equipment specifications for reliable performance.

This component directly replaces Mercury part numbers 803529T06, 803529T03, 803529T02, 803529T1, and 803529T. It also serves as a replacement for Tohatsu/Nissan part numbers 3H6-04000-1, 3H6-04000-3, 3H6-04000-4, and 3H6040000M through 3H6040007M.

• Installation: Mounts as a direct replacement for the original pump.
• Fuel Compatibility: Designed for use with Gasoline.
• Package Includes: 1 x Fuel Pump.

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.

Mercury/Mariner 4-Stroke

Confirm your engine model/year in the table below.

Tohatsu/Nissan 4-Stroke

Technical Specifications

Package Contents

• 1 x Fuel Pump (803529T06/3H6-04000)

Installation Guide

1. Disconnect the Battery: Ensure the engine is off and disconnect the negative battery terminal for safety.
2. Relieve Fuel Pressure: Safely relieve any pressure in the fuel system according to your service manual.
3. Locate and Disconnect Fuel Lines: Place a rag under the fuel pump to catch any spills and carefully disconnect the inlet and outlet fuel lines.
4. Remove Old Fuel Pump: Unbolt the existing fuel pump from the engine block.
5. Install New Pump: Mount the new fuel pump, ensuring it is securely fastened.
6. Reconnect Fuel Lines: Attach the fuel lines to the new pump, making sure the connections are tight to prevent leaks.
7. Reconnect Battery: Reconnect the negative battery terminal.
8. Prime and Test: Prime the fuel system and start the engine. Check carefully for any fuel leaks around the pump and its connections.

Troubleshooting & FAQ

How can I verify this fuel pump fits my specific outboard motor?

The best way to ensure compatibility is to match your existing part number to the ones listed in our "Part Number Cross-Reference" table. Additionally, check your engine's model, horsepower, and year against our "Compatible Engine Models" list. For Mercury owners, using the serial number lookup guide linked above provides the highest accuracy.

What are common symptoms of a faulty fuel pump in an outboard engine?

Common signs include the engine sputtering or bogging down at high speeds, a noticeable loss of power, difficulty starting, or frequent stalling. The engine may also refuse to start if the pump has failed completely.

How often should I replace my fuel pump?

There is no fixed replacement interval for fuel pumps. Replacement is typically done when performance degrades or the pump fails. Regular fuel system maintenance, including using clean fuel and replacing filters, can extend the life of your fuel pump.

OEM vs. Aftermarket?

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.

How fast do you ship and how much does it cost?

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.

What is your warranty and return policy?

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.