Fuel Pump – Fits Mercury/Mariner 4-6 HP & Tohatsu/Nissan 4-9.8 HP 4-Stroke (Replaces 803529T06, 3H6-04000-7)
Fuel Pump – Fits Mercury/Mariner 4-6 HP & Tohatsu/Nissan 4-9.8 HP 4-Stroke (Replaces 803529T06, 3H6-04000-7) 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 Mercury/Mariner 4-6 HP & Tohatsu/Nissan 4-9.8 ...
Product Details
This is a high-quality aftermarket Fuel Pump – Fits Mercury/Mariner 4-6 HP & Tohatsu/Nissan 4-9.8 HP 4-Stroke (Replaces 803529T06, 3H6-04000-7). It is designed as a direct-fit mechanical fuel pump assembly for a wide range of Tohatsu/Nissan 4 HP to 9.8 HP and Mercury/Mariner 4 HP to 6 HP 4-stroke outboard engines manufactured from 2003 to the present.
This component provides a reliable interchange for Mercury part number 803529T06 and its predecessors, as well as Tohatsu part number 3H6-04000-7 and its earlier versions.
- Engineered for direct OEM replacement installation.
- Manufactured in an ISO9002 certified facility for consistent quality.
- Includes one complete fuel pump assembly.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Mercury/Mariner | 803529T06 | Supersedes 803529T01, 803529T02, 803529T03 |
| Mercury/Mariner | 803529T03 | Superseded by 803529T06 |
| Mercury/Mariner | 803529T02 | Superseded by 803529T06 |
| Mercury/Mariner | 803529T1 | Superseded by 803529T06 |
| Tohatsu/Nissan | 3H6-04000-7 | Supersedes 3H6-04000-0 through 3H6-04000-6 |
| JLM Marine | 3H604000 | Aftermarket equivalent |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Tohatsu & Nissan Owners: This fuel pump fits all 4-stroke models from 4 HP to 9.8 HP made since 2003. The part number 3H6-04000-7 is the current replacement for all prior versions.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Tohatsu | MFS4A2 | 4 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Tohatsu | MFS4B | 4 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Tohatsu | MFS5A2 | 5 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Tohatsu | MFS5B | 5 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Tohatsu | MFS6A2 | 6 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Tohatsu | MFS6B | 6 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Tohatsu | MFS8A | 8 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Tohatsu | MFS8A2 | 8 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Tohatsu | MFS8A3 | 8 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Tohatsu | MFS9.8A | 9.8 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Tohatsu | MFS9.8A2 | 9.8 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Tohatsu | MFS9.8A3 | 9.8 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Nissan | NSF4A2 | 4 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Nissan | NSF5A2 | 5 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Nissan | NSF6A2 | 6 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Nissan | NSF8A | 8 | 4-Stroke | 2003–present | 3H6-04000-7 |
| Nissan | NSF9.8A | 9.8 | 4-Stroke | 2003–present | 3H6-04000-7 |
For Mercury & Mariner Owners: This pump is used on 4, 5, and 6 HP 4-stroke models built since 2003. Verify that your engine requires OEM part 803529T06 or an earlier equivalent.
| Brand | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|
| Mercury | 4 | 4-Stroke | 2003–present | 803529T06 |
| Mercury | 5 | 4-Stroke | 2003–present | 803529T06 |
| Mercury | 6 | 4-Stroke | 2003–present | 803529T06 |
| Mariner | 4 | 4-Stroke | 2003–present | 803529T06 |
| Mariner | 5 | 4-Stroke | 2003–present | 803529T06 |
| Mariner | 6 | 4-Stroke | 2003–present | 803529T06 |
Technical Specs
- Product Type
- Mechanical Fuel Pump Assembly
- Installation
- Direct OEM Replacement
- Fuel Type
- Gasoline
- Connection
- 0.75 inches (19.05 mm) Hose Barb
- Housing Material
- Aluminum, Alloy Steel
- Housing Color
- Black/Silver
- Weight
- 0.17 kg (0.37 lb)
- Fitting Type
- Barb
- Warranty
- Varies by retailer (typically 1 year)
- Production Standard
- ISO9002 certified facility
What’s in the Box
- 1 x Fuel Pump Assembly (Replaces 3H6-04000-7 / 803529T06)
Installation Notes
- Disconnect the battery and ensure the work area is well-ventilated.
- Relieve any pressure in the fuel system. Place a rag under the fuel line connections to catch spills.
- Carefully disconnect the inlet and outlet fuel lines from the old pump.
- Remove the mounting bolts securing the fuel pump to the engine block.
- Remove the old fuel pump. Clean the mounting surface of any old gasket material or debris.
- Position the new fuel pump assembly and install the mounting bolts, tightening them to the manufacturer's specified torque.
- Reconnect the fuel lines to the new pump, ensuring a secure fit.
- Reconnect the battery.
- Prime the fuel system according to your engine's manual and check thoroughly for any fuel leaks before starting the engine.
Troubleshooting & FAQ
How do I know if this fuel pump fits my engine?
Confirm your engine's model, horsepower, and year fall within the ranges listed in the compatibility tables. Most importantly, verify your existing fuel pump's part number matches one of the OEM or aftermarket numbers listed in the Part Number Matrix.
What are the signs of a failing fuel pump?
Common symptoms of a bad fuel pump include the engine struggling to start, sputtering or losing power at high speeds, bogging down under acceleration, or failing to start at all.
What is the difference between the Tohatsu part numbers (-0, -3, -7, etc.)?
The different suffixes on Tohatsu part number 3H6-04000 represent minor revisions over the years. Part number 3H6-04000-7 is the latest version and is fully backward-compatible, superseding all previous iterations from -0 to -6.
Is any special maintenance required for this fuel pump?
No specific maintenance is required for the pump itself. However, to ensure a long service life, always use fresh, clean fuel and adhere to your engine manufacturer's recommended schedule for replacing fuel filters.
Why is my OEM part better?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials and performance. Our parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.
How fast do you ship?
We ship worldwide quickly—typical transit time is 5–15 days. Standard shipping is free for most orders, and expedited options are available at checkout where applicable.
What is the warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard window for items that are unused and in their original condition. See our full policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an original equipment manufacturer (OEM) component.
- Professional installation is highly recommended for safety and optimal performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.
- Fast Global Fulfillment — We offer free standard delivery to most regions, with typical transit times of just 5–15 days.
- Manufacturer-Direct Value — By working directly with manufacturers, we provide fair pricing without compromising on materials or quality control.
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