3H6-04000-3 Fuel Pump Assembly for Mercury Tohatsu Mariner MFS4A2 MFS4B MFS5A2 MFS5B MFS6A2 MFS6B MFS8A MFS8A2 MFS8A3 MFS9.8A MFS9.8A2 MFS9.8A3 | JLM Marine

Fuel Pump Assembly for Mercury Tohatsu Mariner MFS4A2 MFS4B MFS5A2 MFS5B MFS6A2 MFS6B MFS8A MFS8A2 MFS8A3 MFS9.8A MFS9.8A2 MFS9.8A3

This fuel pump assembly is engineered for Tohatsu 4-stroke outboards ranging from 4 HP to 9.8 HP, as well as Mercury/Mariner 4-stroke models from 4 HP to 6 HP. Built to deliver reliable fuel delivery for gasoline-powered marine engines, this replacement ensures consistent performance across multiple MFS series models.

This assembly directly replaces OEM part number 3H6-04000-3 and cross-references with Tohatsu part number 3H6-04000-7 and Quicksilver part numbers 803529T 01/02/03/04/05/06/07. It provides broad compatibility across Tohatsu MFS models and select Mercury/Mariner outboards.

• Complete assembly includes fuel pump, O-ring, and mounting clips
• Designed for gasoline 4-stroke outboard engines
• Direct-fit replacement for simplified installation

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here's a guide to help you identify your engine's serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

Your purchase includes the following components:

• 1 × Fuel Pump Assembly
• 1 × O-ring
• 2 × Mounting Clips

Installation Guide

1. Disconnect the battery and turn off the fuel supply to ensure safety during installation.
2. Remove the engine cover to access the fuel pump assembly mounted on the engine block.
3. Disconnect the fuel lines from the old pump, noting their positions for correct reassembly.
4. Remove the mounting clips or fasteners securing the old fuel pump to the engine.
5. Carefully pull the old pump away from the engine, taking care not to damage surrounding components.
6. Clean the mounting surface on the engine block to ensure a proper seal.
7. Position the new O-ring onto the fuel pump or mounting surface as specified in your engine's service manual.
8. Align the new fuel pump assembly with the mounting holes and gently press it into place.
9. Secure the pump using the provided mounting clips, ensuring they are fully seated.
10. Reconnect the fuel lines to the corresponding inlet and outlet ports on the new pump.
11. Restore the fuel supply and battery connection, then start the engine and check for leaks.
12. Reinstall the engine cover and perform a brief test run to verify proper fuel delivery and engine performance.

Troubleshooting & FAQ

Q: How do I confirm this fuel pump fits my engine?
A: Check the Compatible Engine Models table above and verify your engine's brand, model number, and horsepower rating. Cross-reference the OEM part numbers listed (3H6-04000-3, 3H6-04000-7, or 803529T series) with your engine's service manual or the part number on your existing fuel pump.

Q: What are the signs that my fuel pump needs replacement?
A: Common symptoms include difficulty starting the engine, engine sputtering or stalling at idle or under load, inconsistent RPM, and visible fuel leaks around the pump area. If you experience any of these issues, inspect your fuel pump for wear or damage.

Q: How often should I replace the fuel pump on my outboard?
A: Fuel pumps typically last several years under normal operating conditions. However, replacement intervals depend on usage, fuel quality, and maintenance practices. Inspect the pump annually and replace it if you notice performance issues, cracks, or leaks.

Q: Can I install this fuel pump myself, or do I need a mechanic?
A: Basic mechanical skills and familiarity with outboard engines are sufficient for installation. Follow the step-by-step guide above and consult your engine's service manual. If you're uncomfortable working with fuel systems, professional installation is recommended for safety.

Q: Is this an OEM part or aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.