Fuel Pump – Fits Tohatsu/Nissan MFS/NSF 4-9.8 HP, Mercury/Mariner 4-6 HP 4-Stroke (Replaces 3H6-04000-7, 803529T06)

$28.40 $45.00

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Fuel Pump – Fits Tohatsu/Nissan MFS/NSF 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.

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

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This aftermarket Fuel Pump – Fits Tohatsu/Nissan MFS/NSF 4-9.8 HP & Mercury/Mariner 4-6 HP 4-Stroke is designed as a direct replacement for original stock fuel pumps. It ensures reliable fuel delivery for Tohatsu/Nissan 4 HP to 9.8 HP 4-Stroke outboards (MFS and NSF series) and is also compatible with Mercury/Mariner 4 HP to 6 HP 4-Stroke outboards that are based on the Tohatsu powerhead design.

This assembly provides a direct interchange for Tohatsu/Nissan part numbers 3H6-04000-0 through 3H6-04000-7 and Mercury/Mariner references 803529T01, 803529T02, 803529T03, and 803529T06.

Engineered for direct-fit installation.
Manufactured in an ISO9002 certified facility for quality assurance.
Comes with a 1-year aftermarket warranty.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number	Superseded By
Tohatsu / Nissan	3H6-04000-0	3H6-04000-7
Tohatsu / Nissan	3H6-04000-1	3H6-04000-7
Tohatsu / Nissan	3H6-04000-2	3H6-04000-7
Tohatsu / Nissan	3H6-04000-3	3H6-04000-7
Tohatsu / Nissan	3H6-04000-4	3H6-04000-7
Tohatsu / Nissan	3H6-04000-5	3H6-04000-7
Tohatsu / Nissan	3H6-04000-6	3H6-04000-7
Mercury / Mariner	803529T01	803529T06
Mercury / Mariner	803529T02	803529T06
Mercury / Mariner	803529T03	803529T06

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Tohatsu/Nissan: This fuel pump fits MFS and NSF series 4-stroke outboards from 4 HP to 9.8 HP. Check your model number against the list below.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.
Tohatsu	MFS4A2	4	4-Stroke		3H6-04000-7
Tohatsu	MFS4B	4	4-Stroke		3H6-04000-7
Tohatsu	MFS4C	4	4-Stroke	2011–2014	3H6-04000-7
Tohatsu	MFS5A2	5	4-Stroke		3H6-04000-7
Tohatsu	MFS5B	5	4-Stroke		3H6-04000-7
Tohatsu	MFS5C	5	4-Stroke	2011–2014	3H6-04000-7
Tohatsu	MFS6A2	6	4-Stroke		3H6-04000-7
Tohatsu	MFS6B	6	4-Stroke		3H6-04000-7
Tohatsu	MFS6C	6	4-Stroke	2011–2014	3H6-04000-7
Tohatsu	MFS8A	8	4-Stroke		3H6-04000-7
Tohatsu	MFS8A2	8	4-Stroke		3H6-04000-7
Tohatsu	MFS8A3	8	4-Stroke	2006–2014	3H6-04000-7
Tohatsu	MFS9.8A	9.8	4-Stroke		3H6-04000-7
Tohatsu	MFS9.8A2	9.8	4-Stroke		3H6-04000-7
Tohatsu	MFS9.8A3	9.8	4-Stroke	2006–2014	3H6-04000-7
Nissan	NSF4A2	4	4-Stroke		3H6-04000-7
Nissan	NSF4B	4	4-Stroke		3H6-04000-7
Nissan	NSF4C	4	4-Stroke	2011–2014	3H6-04000-7
Nissan	NSF5A2	5	4-Stroke		3H6-04000-7
Nissan	NSF5B	5	4-Stroke		3H6-04000-7
Nissan	NSF5C	5	4-Stroke	2011–2014	3H6-04000-7
Nissan	NSF6A2	6	4-Stroke		3H6-04000-7
Nissan	NSF6B	6	4-Stroke		3H6-04000-7
Nissan	NSF6C	6	4-Stroke	2011–2014	3H6-04000-7
Nissan	NSF8A	8	4-Stroke		3H6-04000-7
Nissan	NSF8A2	8	4-Stroke		3H6-04000-7
Nissan	NSF8A3	8	4-Stroke	2006–2014	3H6-04000-7
Nissan	NSF9.8A	9.8	4-Stroke		3H6-04000-7
Nissan	NSF9.8A2	9.8	4-Stroke		3H6-04000-7
Nissan	NSF9.8A3	9.8	4-Stroke	2006–2014	3H6-04000-7

Mercury/Mariner: Fits various 4, 5, and 6 HP 4-stroke models using the Tohatsu powerhead. Confirm compatibility by matching your existing part number to one of the references in the Part Number Matrix above (e.g., 803529T06).

Technical Specs

Product Type: Fuel Pump Assembly
Installation: Direct OEM Replacement
Fuel Type: Gasoline
Connection: Hose Barb
Housing Material: Alloy/Plastic
Housing Color: Black/Silver
Fitting Type: Hose Barb
Warranty: 1 Year (Aftermarket)
Production Standard: ISO9002 certified factory

What’s in the Box

1 x Fuel Pump Assembly (Replaces 3H6-04000-7)

Installation Notes

Ensure the engine is off and cool. Disconnect the battery negative terminal for safety.
Relieve fuel system pressure by carefully disconnecting the main fuel line into a suitable container.
Note the orientation of the inlet, outlet, and any vacuum lines connected to the old fuel pump. Use tape or markers to label each line.
Disconnect all fuel lines and electrical connectors from the old pump.
Unbolt and remove the old fuel pump assembly from the engine block.
Clean the mounting surface to ensure a proper seal with the new pump.
Install the new fuel pump assembly, ensuring it is correctly oriented. Secure the mounting bolts to the manufacturer's specified torque.
Reconnect all fuel and vacuum lines to the correct ports on the new pump.
Reconnect the battery. Prime the fuel system if required by your engine's manual.
Start the engine and carefully inspect the pump and all connections for any signs of fuel leaks before operating your watercraft.

Troubleshooting & FAQ

How do I know if this fuel pump fits my engine?

The best way is to match the part number from your old fuel pump to one of the numbers listed in our Part Number Matrix. If you cannot find a part number, check our Engine & Model Compatibility table for your specific model and year. Visually comparing your old part to our product images is also a critical final step.

What are common signs of a failing fuel pump?

Symptoms of a bad fuel pump include engine sputtering, loss of power especially under load, difficulty starting, or the engine dying completely. You might also notice fuel starvation when accelerating.

Is there a recommended replacement interval for this pump?

There is no fixed replacement interval for outboard fuel pumps. They are typically replaced when they fail or show signs of wear. Regular fuel filter changes and using clean, high-quality fuel can extend the life of your pump.

Can I install this fuel pump myself?

Yes, installation is straightforward for those with mechanical experience. However, because it involves the fuel system, we recommend professional installation to ensure safety and proper function. Always work in a well-ventilated area and take precautions against fuel spills.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 facility, with batch-inspections for consistency.

Shipping speed & cost?

We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options will appear at checkout where available.

Warranty & returns?

This part is covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. See our policy page or reach out for instructions.

Safety & Important Info

Verify images and specifications against 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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