Fuel Pump – Fits Mercury Marine 4-6 HP & Tohatsu Nissan 4-9.8 HP (Replaces 803529T01, 803529T02, 803529T06)

Fuel Pump – Fits Mercury Marine 4-6 HP & Tohatsu Nissan 4-9.8 HP

This aftermarket fuel pump is designed for a precise fit on specific Mercury Marine 4-6 HP and Tohatsu/Nissan 4-9.8 HP 4-Stroke outboard engines. It serves as a direct replacement component, restoring reliable fuel delivery for optimal engine performance.

This unit directly replaces Mercury part numbers 803529T, 803529T01, 803529T02, 803529T03, and 803529T06, as well as Tohatsu/Nissan part numbers 3H6-04000-0 through 3H6-04000-7.

• Complete Kit: Includes one fuel pump, two clamps/clips, and one O-ring for a comprehensive installation.
• Fuel Compatibility: Designed for use with Gasoline.
• Installation Method: This is a mechanical pump that mounts to the transom and is activated by the engine's camshaft.

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.

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Fuel pump (803529T01/3H6-04000-1)
• 2 x Clamps/clips (54-95395)
• 1 x O-ring (25-803513)

Installation Guide

1. Safety First: Disconnect the battery and work in a well-ventilated area. Ensure the engine is cool.
2. Locate the Pump: Identify the existing fuel pump on the engine block.
3. Disconnect Lines: Carefully disconnect the fuel inlet and outlet lines. Have rags ready to catch any spilled fuel.
4. Remove Old Pump: Unbolt the old fuel pump from the engine. Note the orientation of the actuator arm.
5. Clean Surface: Clean the mounting surface on the engine block to ensure a good seal with the new O-ring.
6. Install New Pump: Place the new O-ring and install the new fuel pump, ensuring the actuator arm is correctly positioned against the camshaft.
7. Secure Bolts: Tighten the mounting bolts to the manufacturer's recommended torque specifications.
8. Reconnect Lines: Securely attach the fuel inlet and outlet hoses and clamps.
9. Prime the System: Reconnect the battery. Use the primer bulb (if equipped) to fill the fuel system.
10. Check for Leaks: Start the engine and carefully inspect for any fuel leaks around the pump and connections.

Troubleshooting & FAQ

Q: How do I confirm this fuel pump will fit my specific engine?

A: The best way is to match your existing part number to the ones listed in our cross-reference table. You can also check your engine's model and HP against our compatible models list. For Mercury owners, our Serial Number Guide can help you identify your engine details.

Q: What are the signs of a failing fuel pump?

A: Common symptoms include difficulty starting the engine, stalling at low speeds, engine hesitation or loss of power during acceleration, and sputtering at high speeds. A visible fuel leak from the pump body is also a clear sign of failure.

Q: Is this difficult to install myself?

A: This is a mechanical pump, and installation is straightforward for those with basic mechanical skills. However, as it involves the fuel system, we recommend professional installation if you are not completely comfortable with the process to ensure safety and proper function.

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.