Fuel Pump – Fits Mercury/Mariner/Tohatsu/Nissan 9.9-30 HP & Johnson/Evinrude 15 HP (Replaces 803529T04, 3H8-04000-1)
Fuel Pump – Fits Mercury/Mariner/Tohatsu/Nissan 9.9-30 HP & Johnson/Evinrude 15 HP (Replaces 803529T04, 3H8-04000-1) 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 – Fits Mercury/Mariner/Tohatsu/Nissan 9.9-30 HP & Joh...
Product Details
This pulse-driven mechanical Fuel Pump is designed for a wide range of outboard motors, including Mercury/Mariner 9.9–30 HP 4-Stroke models (2005–present), Tohatsu/Nissan 9.9–30 HP 4-Stroke models (2002–2018), and select Johnson/Evinrude 15 HP 2-Stroke models.
It serves as a direct cross-reference for Mercury part numbers 803529T04 and 803529A04, Tohatsu/Nissan 3H8-04000-1, and Johnson/Evinrude 5041064.
- Features a simple two-bolt mounting system for straightforward installation.
- Constructed with a corrosion-resistant metal and plastic housing to withstand demanding marine environments.
- Includes a new O-ring and spring clamps for a complete seal.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Mercury | 803529A04 | Superseded by 803529T04. |
| Mercury | 803529T04 | Primary replacement number. |
| Tohatsu / Nissan | 3H8-04000-1 | Interchangeable with 3H8040001 and 3H8040001M. |
| Johnson / Evinrude | 5041064 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury/Mariner: This pump fits a wide range of 4-stroke models from 9.9 to 30 HP built from 2005 to present. As model-specific data is broad, please verify the part number 803529T04 matches your service manual.
For Tohatsu/Nissan: Extensive compatibility with Tohatsu and Nissan 4-stroke engines from 9.9 to 30 HP. Check your specific model and year against the list below to ensure a correct fit.
For Johnson/Evinrude: Compatibility is limited to certain 15 HP 2-stroke models. It is critical to confirm that OEM part number 5041064 is the correct reference for your engine before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | Various 4-Stroke | 9.9 | 4-Stroke | 2005–Present | 803529T04 | Replaces 803529A04 |
| Mercury | Various 4-Stroke | 15 | 4-Stroke | 2005–Present | 803529T04 | Replaces 803529A04 |
| Mercury | Various 4-Stroke | 20 | 4-Stroke | 2005–Present | 803529T04 | Replaces 803529A04 |
| Mercury | Various 4-Stroke | 25 | 4-Stroke | 2005–Present | 803529T04 | Replaces 803529A04 |
| Mercury | Various 4-Stroke | 30 | 4-Stroke | 2005–Present | 803529T04 | Replaces 803529A04 |
| Tohatsu | MFS9.9E EFI | 9.9 | 4-Stroke | 2017–2018 | 3H8-04000-1 | Fuel Pump |
| Tohatsu | MFS9.9B, MFS9.9B2 | 9.9 | 4-Stroke | 2002–2004 | 3H8-04000-1 | Inlet Manifold, Fuel Pump |
| Tohatsu | MFS15E EFI | 15 | 4-Stroke | 2017–2018 | 3H8-04000-1 | Fuel Pump |
| Tohatsu | MFS15B, MFS15B2, MFS15C | 15 | 4-Stroke | 2002–2012 | 3H8-04000-1 | Inlet Manifold, Fuel Pump |
| Tohatsu | MFS20E EFI | 20 | 4-Stroke | 2017–2018 | 3H8-04000-1 | Fuel Pump |
| Tohatsu | MFS20C, MFS20D | 20 | 4-Stroke | 2011–2016 | 3H8-04000-1 | Inlet Manifold, Fuel Pump |
| Tohatsu | MFS25A | 25 | 4-Stroke | 2002–2005 | 3H8-04000-1 | Inlet Manifold, Fuel Pump |
| Tohatsu | MFS25B | 25 | 4-Stroke | 2006–2014 | 3H8-04000-1 | Fuel Pump, Fuel Rail & Vapor Separator |
| Tohatsu | MFS25C | 25 | 4-Stroke | 2015–2018 | 3H8-04000-1 | Fuel System |
| Tohatsu | MFS30A | 30 | 4-Stroke | 2002–2005 | 3H8-04000-1 | Inlet Manifold, Fuel Pump |
| Tohatsu | MFS30B | 30 | 4-Stroke | 2005–2014 | 3H8-04000-1 | Fuel Pump, Fuel Rail & Vapor Separator |
| Tohatsu | MFS30C | 30 | 4-Stroke | 2015–2018 | 3H8-04000-1 | Fuel System |
| Nissan | NSF9.9B, NSF9.9B2 | 9.9 | 4-Stroke | 2002–2004 | 3H8-04000-1 | Inlet Manifold, Fuel Pump |
| Nissan | NSF15B, NSF15B2, NSF15C | 15 | 4-Stroke | 2002–2013 | 3H8-04000-1 | Inlet Manifold, Fuel Pump |
| Nissan | NSF20C | 20 | 4-Stroke | 2008 | 3H8-04000-1 | Inlet Manifold, Fuel Pump |
| Nissan | NSF25A | 25 | 4-Stroke | 2002–2005 | 3H8-04000-1 | Inlet Manifold, Fuel Pump |
| Nissan | NSF25B | 25 | 4-Stroke | 2006–2014 | 3H8-04000-1 | Fuel Pump, Fuel Rail & Vapor Separator |
| Nissan | NSF30A | 30 | 4-Stroke | 2002–2005 | 3H8-04000-1 | Inlet Manifold, Fuel Pump |
| Nissan | NSF30B | 30 | 4-Stroke | 2005–2014 | 3H8-04000-1 | Fuel Pump, Fuel Rail & Vapor Separator |
| Johnson | Various Models | 15 | 2-Stroke | 1993–2007 | 5041064 | Limited compatibility |
| Evinrude | Various Models | 15 | 2-Stroke | 1993–2007 | 5041064 | Limited compatibility |
Technical Specs
- Product Type
- Mechanical Fuel Pump
- Drive System
- Pulse-Driven
- Installation
- Two-bolt mounting system
- Fuel Type
- Gasoline
- Connection Type
- Hose barb fittings
- Housing Material
- Corrosion-resistant metal and plastic
- Housing Color
- Black/Silver
- Dimensions
- Approximately 89 × 76 × 38 mm (3.5 × 3.0 × 1.5 inches)
- Weight
- Approximately 0.07 kg (0.15 lbs)
- Working Pressure
- Meets OEM specifications
- Operating Temperature
- -20 to 80°C (-4 to 176°F)
What’s in the Box
- 1 x Fuel Pump Assembly
- 1 x O-Ring
- 2 x Metal Spring Clamps
Installation Notes
- Always work in a well-ventilated area and disconnect the negative battery terminal before starting.
- Relieve fuel system pressure according to your service manual and place rags to catch any fuel spills.
- Carefully disconnect the fuel inlet, outlet, and pulse hoses from the old pump.
- Unbolt and remove the old pump assembly and its gasket or O-ring.
- Thoroughly clean the mounting surface on the engine block to ensure a proper seal.
- Position the new pump with its O-ring, then install and tighten the mounting bolts to the specified torque.
- Securely reconnect all hoses using the new spring clamps provided.
- Reconnect the battery, prime the fuel system as needed, and start the engine. Carefully inspect the pump and all connections for any leaks.
Troubleshooting & FAQ
What are common signs of a failing fuel pump?
Symptoms include engine hesitation or stumbling, especially at high speeds, difficulty starting, rough idling, or a complete failure to start. A visual inspection may also reveal fuel leaking from the pump housing or connected lines.
How can I be sure this fits my Mercury/Mariner engine?
Because Mercury uses this pump across many models, the best way to confirm fitment is by matching your old part number to 803529T04. While it fits most 9.9–30 HP 4-stroke models from 2005-present, checking the part number is the only way to guarantee compatibility.
Why is Johnson/Evinrude compatibility listed as "limited"?
This pump only fits specific Johnson/Evinrude 15 HP 2-stroke models that use OEM part number 5041064. Its primary design is for 4-stroke applications, so you must confirm this exact part number for a 2-stroke engine before ordering.
Is this fuel pump compatible with ethanol-blended fuels?
Yes, this aftermarket pump is built with materials designed to handle standard ethanol-blended gasoline (up to E10). Using fuels with higher ethanol concentrations is not recommended and may reduce the service life of the pump and other fuel system components.
What is a "pulse-driven" pump?
A pulse-driven mechanical pump uses the changing pressure within the engine's crankcase to operate. As the piston moves, the pressure fluctuation moves a diaphragm inside the pump, which draws fuel from the tank and sends it to the carburetor without needing any electrical power.
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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