Fuel Pump – Fits Tohatsu/Nissan 4-9.8 HP & Mercury/Mariner 4-6 HP (Replaces 3H6-04000, 803529T)
Fuel Pump – Fits Tohatsu/Nissan 4-9.8 HP & Mercury/Mariner 4-6 HP (Replaces 3H6-04000, 803529T) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Fuel Pump – Fits Tohatsu/Nissan 4-9.8 HP & Mercury/Mariner 4-6 ...
Product Details
This replacement Fuel Pump – Fits Tohatsu/Nissan 4-9.8 HP & Mercury/Mariner 4-6 HP (Replaces 3H6-04000, 803529T) is engineered for a precise fit on a range of 4-stroke outboard motors. It covers Tohatsu and Nissan models from 4 HP to 9.8 HP manufactured between 2002 and 2014, as well as Mercury and Mariner 4 HP to 6 HP 4-stroke engines.
This unit is a direct interchange for Tohatsu part numbers 3H6-04000-0M through 3H6-04000-7M and Mercury numbers including 803529T, 803529T01, 803529T02, 803529T03, and 803529T06.
- Engineered for direct-fit installation, no modifications required.
- Durable metal housing ensures longevity in marine environments.
- Includes one complete fuel pump assembly for a streamlined repair.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| 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 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fitment data is for Tohatsu and Nissan models. While this part also replaces Mercury/Mariner equivalents, specific model compatibility for those brands is not available.
| 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 Specs
- Product Type
- Fuel Pump
- Installation
- Direct OEM Replacement
- Fuel Type
- Gasoline
- Housing Material
- Metal
What’s in the Box
- 1 x Fuel Pump Assembly (3H6-04000/803529T)
Installation Notes
- Ensure the engine is off and cool. Disconnect the battery and relieve any pressure in the fuel system.
- Place a rag under the fuel pump to catch any fuel spillage.
- Carefully disconnect the fuel inlet and outlet lines. Note their orientation.
- Remove the mounting bolts securing the old fuel pump to the engine block.
- Clean the mounting surface and install the new fuel pump.
- Tighten the mounting bolts to the manufacturer's specified torque.
- Reconnect the fuel lines to the correct ports and secure them with clamps.
- Reconnect the battery, prime the fuel system according to your engine's manual, and check for leaks before starting the engine.
Troubleshooting & FAQ
How do I know if this fuel pump fits my engine?
First, cross-reference your existing part number with the list in our Part Number Matrix. Second, verify your engine's specific model and year in the Engine & Model Compatibility table. If your part number and model match, it will fit.
What are common signs of a failing fuel pump?
Symptoms of a bad fuel pump include the engine bogging down or sputtering at high speed, a noticeable loss of power, difficulty starting the engine, or the engine failing to start at all.
Does this pump come with new gaskets?
This package contains the fuel pump assembly only. Depending on your engine, existing gaskets may be reusable if in excellent condition, but we recommend installing a new gasket to ensure a proper, leak-free seal.
What is the typical lifespan of a fuel pump?
Lifespan varies based on usage, fuel quality, and operating conditions. There is no set replacement interval; however, it's wise to replace it as a preventative measure during a major engine service or if you notice any performance issues.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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