Carburetor – Fits Mercury/Mariner 2–6 HP & Tohatsu/Nissan MFS/NFS 3.5–6 HP 4-Stroke Outboards (Replaces 3R1-03200-1, 853720T25)

Carburetor – Fits Mercury/Mariner 2–6 HP & Tohatsu/Nissan MFS/NFS 3.5–6 HP 4-Stroke Outboards

This carburetor assembly is a direct-fit replacement for a range of Mercury/Mariner 2–6 HP and Tohatsu/Nissan 3.5–6 HP 4-stroke outboard engines, covering various models from the early 2000s to the present.

It is designed to replace original equipment part numbers, including Mercury 803522T-series, 853720T25, 8M0053670, and Tohatsu 3R1-03200-1, ensuring a precise fit and reliable fuel delivery for smooth engine operation.

• Installation Method: Direct Replacement
• Compatible Fuel Type: Gasoline
• Package Contents: Includes one complete carburetor assembly.

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.

For Tohatsu and Nissan models, confirm your engine model/year in the table below.

Mercury/Mariner Models

Tohatsu/Nissan Models

Technical Specifications

Package Contents

• 1 x Carburetor Assembly (Replaces 3R1-03200-1/853720T25/803522T03)

Installation Guide

1. Safety First: Shut off the fuel supply and disconnect the negative battery terminal.
2. Access the Carburetor: Remove the engine cowling to expose the carburetor.
3. Disconnect Lines: Carefully disconnect the main fuel line from the carburetor. Be prepared for minor fuel spillage.
4. Detach Linkages: Unclip or unscrew the throttle and choke linkages connected to the carburetor. Note their orientation for reassembly.
5. Remove Old Carburetor: Unscrew the mounting nuts or bolts that secure the carburetor to the intake manifold.
6. Clean Surface: Gently remove the old carburetor and its gasket. Clean the mounting surface of the intake manifold to ensure a good seal.
7. Install New Carburetor: Place the new gasket and carburetor assembly onto the intake manifold studs or bolt holes.
8. Secure in Place: Tighten the mounting nuts or bolts evenly to the manufacturer's recommended torque. Do not overtighten.
9. Reconnect Components: Reattach the throttle and choke linkages, followed by the fuel line.
10. Final Checks: Reconnect the battery. Turn on the fuel supply and check for any leaks around the carburetor and fuel lines.
11. Test Operation: Start the engine and let it warm up. Check for smooth idling and adjust the idle speed screw if necessary.
12. Reassemble: Once satisfied with performance, replace the engine cowling.

Troubleshooting & FAQ

Q: How do I confirm this carburetor fits my engine?
A: Review the "Compatible Engine Models" and "Part Number Cross-Reference" tables. This carburetor is specifically designed for certain Mercury/Mariner 2–6 HP and Tohatsu/Nissan 3.5–6 HP 4-stroke models. The most reliable method is to match your original carburetor's part number to the ones listed.

Q: What are the signs my old carburetor needs to be replaced?
A: Common symptoms include difficulty starting, rough or unstable idling, stalling at low speeds, poor acceleration, increased fuel consumption, or black smoke from the exhaust. Visible fuel leaks or cracks on the carburetor body are also clear indicators that a replacement is needed.

Q: Is any adjustment required after installation?
A: Our carburetors are preset to function for most compatible models upon installation. However, minor adjustments to the idle speed screw may be necessary to achieve optimal performance based on your specific engine's condition and local atmospheric conditions.

Q: OEM vs. 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.