Fuel Pump Assembly – Fits Tohatsu/Nissan 4-9.8 HP & Mercury/Mariner 4-6 HP 4-Stroke (Replaces 3H6-04000-7, 803529T06)
Fuel Pump Assembly – Fits Tohatsu/Nissan 4-9.8 HP & Mercury/Mariner 4-6 HP 4-Stroke (Replaces 3H6-04000-7, 803529T06) is backordered and will ship as soon as it is back in stock.
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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.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Fuel Pump Assembly – Fits Tohatsu/Nissan 4-9.8 HP & Mercury/Mar...
Product Details
This Fuel Pump Assembly is an aftermarket replacement designed for a range of 4-stroke outboard motors, including Tohatsu/Nissan 4–9.8 HP models and Mercury/Mariner 4–6 HP models. It ensures reliable fuel delivery, restoring engine performance and efficiency.
It serves as a direct interchange for Tohatsu part number 3H6-04000-7 and Mercury part number 803529T06, superseding several earlier versions from both manufacturers.
- Engineered as a direct OEM-equivalent replacement for simple installation.
- Features two hose barbs for secure inlet and outlet fuel line connections.
- Manufactured in an ISO 9002 certified facility to meet strict quality standards.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By |
|---|---|---|
| Tohatsu | 3H6-04000-0 | 3H6-04000-7 |
| Tohatsu | 3H6-04000-1 | 3H6-04000-7 |
| Tohatsu | 3H6-04000-2 | 3H6-04000-7 |
| Tohatsu | 3H6-04000-3 | 3H6-04000-7 |
| Tohatsu | 3H6-04000-4 | 3H6-04000-7 |
| Tohatsu | 3H6-04000-5 | 3H6-04000-7 |
| Tohatsu | 3H6-04000-6 | 3H6-04000-7 |
| Mercury | 803529T1 | 803529T06 |
| Mercury | 803529T02 | 803529T06 |
| Mercury | 803529T03 | 803529T06 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Tohatsu & Nissan Owners: This fuel pump fits a wide range of MFS and NSF 4-stroke models from 4 HP to 9.8 HP. It directly replaces the 3H6-04000-7 part number and all its preceding versions.
For Mercury & Mariner Owners: This pump is compatible with 4 HP, 5 HP, and 6 HP 4-stroke outboards requiring part number 803529T06. It also replaces earlier versions T1, T02, and T03.
| Brand | Model | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Tohatsu | MFS4A2 | 4 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Tohatsu | MFS4B | 4 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Tohatsu | MFS5A2 | 5 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Tohatsu | MFS5B | 5 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Tohatsu | MFS6A2 | 6 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Tohatsu | MFS6B | 6 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Tohatsu | MFS8A | 8 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Tohatsu | MFS8A2 | 8 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Tohatsu | MFS8A3 | 8 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Tohatsu | MFS9.8A | 9.8 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Tohatsu | MFS9.8A2 | 9.8 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Tohatsu | MFS9.8A3 | 9.8 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Nissan | NSF4A2 | 4 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Nissan | NSF5A2 | 5 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Nissan | NSF6A2 | 6 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Nissan | NSF8A | 8 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Nissan | NSF9.8A | 9.8 | 4-Stroke | 3H6-04000-7 | Supersedes earlier -0 through -6 versions |
| Mercury | 4 | 4-Stroke | 803529T06 | Also replaces 803529T1, 803529T02, 803529T03 | |
| Mercury | 5 | 4-Stroke | 803529T06 | Also replaces 803529T1, 803529T02, 803529T03 | |
| Mercury | 6 | 4-Stroke | 803529T06 | Also replaces 803529T1, 803529T02, 803529T03 | |
| Mariner | 4 | 4-Stroke | 803529T06 | Also replaces 803529T1, 803529T02, 803529T03 | |
| Mariner | 5 | 4-Stroke | 803529T06 | Also replaces 803529T1, 803529T02, 803529T03 | |
| Mariner | 6 | 4-Stroke | 803529T06 | Also replaces 803529T1, 803529T02, 803529T03 |
Technical Specs
- Product Type
- Fuel Pump Assembly
- Installation
- Direct OEM Replacement
- Fuel Type
- Gasoline
- Connection
- Two hose barbs (inlet/outlet)
- Housing Material
- Alloy
- Housing Color
- Silver/Metallic with black top
- Fitting Type
- Hose barb connections
- Warranty
- Varies by retailer (typically 1-year against manufacturing defects)
- Production Standard
- ISO9002 certified factory
What’s in the Box
- 1 x Fuel Pump Assembly
Installation Notes
- Disconnect the battery and relieve any pressure from the fuel system.
- Place a rag under the fuel pump to catch any gasoline spillage.
- Carefully disconnect the inlet and outlet fuel lines from the pump. Note their orientation.
- Remove the mounting bolts securing the old fuel pump to the engine block.
- Clean the mounting surface to ensure a good seal with the new pump.
- Position the new fuel pump and secure it with the mounting bolts. Do not overtighten.
- Reconnect the fuel lines to the correct inlet/outlet ports on the new pump and secure the clamps.
- Reconnect the battery.
- Prime the fuel system according to your engine's manual and check thoroughly for any leaks before starting the engine.
Troubleshooting & FAQ
How do I know if my fuel pump is failing?
Common signs of a failing fuel pump include engine hesitation or sputtering, stalling, difficulty starting, surging, or a significant loss of power, especially under acceleration or load.
Is this a direct fit for my engine?
This pump is designed as a direct replacement for the specified Tohatsu, Nissan, Mercury, and Mariner models. Please use the Part Number Matrix and Compatibility tables on this page to cross-reference your original part number and engine model to ensure a correct fit.
What is the recommended replacement interval?
There is no universal replacement interval for outboard fuel pumps. They should be inspected during regular service and replaced if you observe signs of physical wear, leakage, or consistent engine performance issues related to fuel delivery.
Does this pump include new gaskets?
This package contains the fuel pump assembly as pictured. Gaskets, seals, or additional hardware are not included unless explicitly listed in the "What’s in the Box" section. Please check if your application requires a new gasket upon installation.
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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