Description
Fuel PumpFits Tohatsu/Nissan 4-9.8 HP & Mercury/Mariner 4-6 HP (Replaces 3H6-04000, 803529T)
This fuel pump assembly is a direct-fit replacement for Tohatsu, Nissan, Mercury, and Mariner outboard motors. It is designed to meet or exceed original equipment specifications for reliable fuel delivery.
This component fits Tohatsu/Nissan 4-9.8 HP 4-stroke engines from 20022014 and Mercury/Mariner 4-6 HP 4-stroke engines. It is a direct replacement for Tohatsu part numbers 3H6-04000-0M through 3H6-04000-7M and Mercury part numbers 803529T, 803529T01, 803529T02, 803529T03, and 803529T06.
- Installation: Direct OEM Replacement
- Housing Material: Metal
- Compatible Fuel Type: Gasoline
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Tohatsu | 3H6-04000-0M |
| Tohatsu | 3H6-04000-1M |
| Tohatsu | 3H6-04000-2M |
| Tohatsu | 3H6-04000-3M |
| Tohatsu | 3H6-04000-4M |
| Tohatsu | 3H6-04000-5M |
| Tohatsu | 3H6-04000-6M |
| Tohatsu | 3H6-04000-7M |
| Mercury | 803529T |
| Mercury | 803529T01 |
| Mercury | 803529T02 |
| Mercury | 803529T03 |
| Mercury | 803529T06 |
Compatible Engine Models
Confirm your engine model/year in the table below. For Mercury owners, heres a guide to help you identify your engines serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Tohatsu | MFS4A2 | 4 | 4-Stroke | 2002 | 3H6-04000 | Carburetor & Fuel Pump section |
| Tohatsu | MFS5A2 | 5 | 4-Stroke | 2002 | 3H6-04000 | Carburetor & Fuel Pump section |
| Tohatsu | MFS6A2 | 6 | 4-Stroke | 2002 | 3H6-04000 | Carburetor & Fuel Pump section |
| Tohatsu | MFS4B | 4 | 4-Stroke | 2005, 2010 | 3H6-04000 | Carburetor & Fuel Pump section |
| Tohatsu | MFS5B | 5 | 4-Stroke | 2005, 2010 | 3H6-04000 | Carburetor & Fuel Pump section |
| Tohatsu | MFS6B | 6 | 4-Stroke | 2005, 2010 | 3H6-04000 | Carburetor & Fuel Pump section |
| Tohatsu | MFS8A2 | 8 | 4-Stroke | 2004 | 3H6-04000 | Intake Manifold & Fuel Pump section |
| Tohatsu | MFS9.8A2 | 9.8 | 4-Stroke | 2004 | 3H6-04000 | Intake Manifold & Fuel Pump section |
| Tohatsu | MFS8A3 | 8 | 4-Stroke | 2006, 2009-2014 | 3H6-04000 | Intake Manifold & Fuel Pump section |
| Tohatsu | MFS9.8A3 | 9.8 | 4-Stroke | 2006, 2009-2014 | 3H6-04000 | Intake Manifold & Fuel Pump section |
| Tohatsu | MFS4C | 4 | 4-Stroke | 2011-2014 | 3H6-04000 | Carburetor & Fuel Pump section |
| Tohatsu | MFS5C | 5 | 4-Stroke | 2011-2014 | 3H6-04000 | Carburetor & Fuel Pump section |
| Tohatsu | MFS6C | 6 | 4-Stroke | 2011-2014 | 3H6-04000 | Carburetor & Fuel Pump section |
| Nissan | NSF4A2 | 4 | 4-Stroke | 2002 | 3H6-04000 | Carburetor & Fuel Pump section |
| Nissan | NSF5A2 | 5 | 4-Stroke | 2002 | 3H6-04000 | Carburetor & Fuel Pump section |
| Nissan | NSF6A2 | 6 | 4-Stroke | 2002 | 3H6-04000 | Carburetor & Fuel Pump section |
| Nissan | NSF4B | 4 | 4-Stroke | 2005, 2010 | 3H6-04000 | Carburetor & Fuel Pump section |
| Nissan | NSF5B | 5 | 4-Stroke | 2005, 2010 | 3H6-04000 | Carburetor & Fuel Pump section |
| Nissan | NSF6B | 6 | 4-Stroke | 2005, 2010 | 3H6-04000 | Carburetor & Fuel Pump section |
| Nissan | NSF8A2 | 8 | 4-Stroke | 2004 | 3H6-04000 | Intake Manifold & Fuel Pump section |
| Nissan | NSF9.8A2 | 9.8 | 4-Stroke | 2004 | 3H6-04000 | Intake Manifold & Fuel Pump section |
| Nissan | NSF8A3 | 8 | 4-Stroke | 2006, 2009-2014 | 3H6-04000 | Intake Manifold & Fuel Pump section |
| Nissan | NSF9.8A3 | 9.8 | 4-Stroke | 2006, 2009-2014 | 3H6-04000 | Intake Manifold & Fuel Pump section |
| Nissan | NSF4C | 4 | 4-Stroke | 2011-2014 | 3H6-04000 | Carburetor & Fuel Pump section |
| Nissan | NSF5C | 5 | 4-Stroke | 2011-2014 | 3H6-04000 | Carburetor & Fuel Pump section |
| Nissan | NSF6C | 6 | 4-Stroke | 2011-2014 | 3H6-04000 | Carburetor & Fuel Pump section |
Technical Specifications
| Specification | Value |
|---|---|
| Product Type | Fuel Pump |
| Installation | Direct OEM Replacement |
| Fuel Type | Gasoline |
| Housing Material | Metal |
Package Contents
1 x Fuel Pump Assembly (3H6-04000/803529T)
Installation Guide
- Disconnect the battery and relieve any pressure in the fuel system.
- Place absorbent rags around the old fuel pump to catch any spilled fuel.
- Carefully disconnect the fuel inlet and outlet lines from the pump.
- Remove the mounting bolts that secure the fuel pump to the engine block.
- Take out the old pump and thoroughly clean the mounting surface, removing any old gasket material.
- Compare the new pump to the old one to ensure a perfect match.
- Position the new fuel pump and install it with the new gasket.
- Tighten the mounting bolts evenly to the manufacturer’s recommended torque.
- Securely reconnect the fuel lines to the new pump.
- Reconnect the battery.
- Prime the fuel system according to your engine’s manual and carefully check all connections for leaks.
- Start the engine, let it idle, and confirm smooth operation without any leaks.
Troubleshooting & FAQ
Q: How do I know if this fuel pump fits my Tohatsu or Mercury engine?
A: This pump fits specific Tohatsu/Nissan 4-9.8 HP 4-stroke models (2002-2014) and Mercury/Mariner 4-6 HP 4-stroke outboards. Please refer to the “Compatible Engine Models” table and cross-reference your engine’s model and year. It directly replaces Tohatsu part numbers starting with 3H6-04000 and Mercury parts like 803529T.
Q: What are the signs of a failing fuel pump?
A: Common symptoms include difficulty starting the engine, stalling at low speeds, rough idling, engine hesitation during acceleration, or a complete loss of power. If you notice these issues, your fuel pump may need inspection or replacement.
Q: Is this a complete assembly?
A: Yes, this is a complete fuel pump assembly. The package includes one pump, as shown in the images. Gaskets or additional fittings are not included unless specified in the package contents.
Q: My engine model is listed, but the part looks different. What should I do?
A: Do not install the part. Manufacturers sometimes make mid-year design changes. Please review the “Important Notes” and verify that the product images and specifications exactly match your original part before purchasing.
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 shippingtypically 515 days worldwideand 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 existeven if your model is listeddo 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 515 days.
- Direct from Manufacturer: Competitive pricing without compromising quality.



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