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 (Replaces 3R1-03200-1, 853720T25) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
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Carburetor – Fits Mercury/Mariner 2–6 HP & Tohatsu/Nissan MFS/N...
Carburetor – Fits Mercury/Mariner 2–6 HP & Tohatsu/Nissan MFS/NFS 3.5–6 HP 4-Stroke Outboards (Replaces 3R1-03200-1, 853720T25) is backordered and will ship as soon as it is back in stock.
Product Details
This is a replacement Carburetor – Fits Mercury/Mariner 2–6 HP & Tohatsu/Nissan MFS/NFS 3.5–6 HP 4-Stroke Outboards, designed for reliable performance in a wide range of engines. It is compatible with various Mercury/Mariner 2–6 HP 4-stroke models from the early 2000s to the present, as well as Tohatsu and Nissan 3.5–6 HP 4-stroke outboards from the MFS/NFS series manufactured since the early 2000s.
It serves as a direct interchange for numerous OEM part numbers, including Mercury 853720T25, 8M0053670, and Tohatsu 3R1-03200-1, ensuring broad compatibility.
- Installs as a direct OEM-style replacement without modification.
- Constructed from durable, die-cast aluminum for longevity in marine environments.
- Engineered to provide a precise air-fuel mixture for smooth combustion and efficient engine operation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury/Mariner | 803522T1 |
| Mercury/Mariner | 803522T2 |
| Mercury/Mariner | 803522T03 |
| Mercury/Mariner | 803522T04 |
| Mercury/Mariner | 803522T05 |
| Mercury/Mariner | 803522T06 |
| Mercury/Mariner | 803522A04 |
| Mercury/Mariner | 8M0053670 |
| Mercury/Mariner | 853720T25 |
| Mercury/Mariner | 898103T51 |
| Mercury/Mariner | 889246T10 |
| Tohatsu/Nissan | 3R1-03200-1 |
| Tohatsu/Nissan | 3R1-03200-1-00 |
| Tohatsu/Nissan | 3AS-03200-0 |
| Tohatsu/Nissan | 3GV-03200-0 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This carburetor fits a range of Mercury and Mariner 4-stroke outboard models from 2.5 to 6 HP.
| Brand | Model | Rated HP | Stroke | OEM Part No. |
|---|---|---|---|---|
| Mercury | F2.5/2.5M | 2.5 | 4-Stroke | 853720T25 |
| Mercury | F3.5/3.5M | 3.5 | 4-Stroke | 853720T25 |
| Mercury | F4/4M | 4 | 4-Stroke | 803522T03 |
| Mercury | F5/5M | 5 | 4-Stroke | 803522T03 |
| Mercury | F6/6M | 6 | 4-Stroke | 803522T03 |
Compatible with various Tohatsu and Nissan 4-stroke outboards, including the MFS and NFS series from 3.5 to 5 HP.
| Brand | Model | Rated HP | Stroke | OEM Part No. |
|---|---|---|---|---|
| Tohatsu | MF3.5 | 3.5 | 4-Stroke | 3R1-03200-1 |
| Tohatsu | MFS4 | 4 | 4-Stroke | 3R1-03200-1 |
| Tohatsu | MFS5 | 5 | 4-Stroke | 3R1-03200-1 |
| Nissan | NFS4 | 4 | 4-Stroke | 3R1-03200-1 |
| Nissan | NFS5 | 5 | 4-Stroke | 3R1-03200-1 |
Technical Specs
- Product Type
- Carburetor Assembly
- Installation
- Direct Replacement
- Fuel Type
- Gasoline
- Connection
- Intake Manifold Mount
- Housing Material
- Metal (Die-cast aluminum)
- Housing Color
- Silver/Machined
- Fitting Type
- Replacement Flange
- Other Technical Attributes
- OEM-compatible carburetor providing precise air-fuel mixture for smooth combustion and reliable operation
What’s in the Box
- 1 x Carburetor Assembly (3R1-03200-1/853720T25/803522T03)
Installation Notes
- Ensure the engine is cool. Disconnect the negative battery terminal and shut off the fuel supply valve.
- Place a rag below the carburetor to catch any spilled fuel.
- Carefully disconnect the fuel line(s) from the carburetor.
- Remove the airbox cover and air filter assembly to access the carburetor.
- Disconnect the throttle linkage and choke linkage (if applicable). Note their positions for reassembly.
- Remove the nuts or bolts securing the carburetor to the intake manifold studs.
- Gently pull the carburetor off, being careful not to damage the old gasket.
- Clean the intake manifold mounting surface thoroughly, removing any old gasket material or debris.
- Position the new gasket and carburetor onto the mounting studs.
- Tighten the mounting nuts or bolts evenly to the manufacturer's recommended torque. Do not overtighten.
- Reconnect all linkages, fuel lines, and any other connections. Reinstall the airbox assembly.
- Turn the fuel supply on, prime if necessary, and check for leaks before starting the engine.
Troubleshooting & FAQ
How do I know if this carburetor fits my specific outboard model?
Check your engine's model, horsepower, and stroke type. Compare your existing carburetor's part number against the comprehensive list of direct replacements provided in our Part Number Matrix. When in doubt, a visual comparison between your old part and our product images is the most reliable method.
What are the signs my old carburetor is failing?
Common symptoms include difficulty starting (hard starts), rough or erratic idling, stalling at low speeds, poor acceleration, increased fuel consumption, or black smoke from the exhaust. Fuel leaks around the carburetor body are also a clear sign of failure.
Is any adjustment needed after installation?
This carburetor is designed as a direct-fit replacement and is often ready to use out of the box. However, minor adjustments to the idle speed or air-fuel mixture screw may be necessary to achieve optimal performance based on your specific engine's condition and local altitude.
What is the recommended maintenance for this carburetor?
To ensure longevity, always use high-quality, fresh fuel with a stabilizer, especially if the engine is used infrequently. Periodically check that all connections are secure and free of leaks. For long-term or winter storage, it is recommended to drain the fuel from the carburetor bowl to prevent gumming and deposits.
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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