Carburetor – Fits Mercury, Tohatsu, Nissan 2-6 HP (Replaces 3R1-03200-1, 853720T25)
Carburetor – Fits Mercury, Tohatsu, Nissan 2-6 HP (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.
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Carburetor – Fits Mercury, Tohatsu, Nissan 2-6 HP (Replaces 3R1-032...
Carburetor – Fits Mercury, Tohatsu, Nissan 2-6 HP (Replaces 3R1-03200-1, 853720T25) is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Carburetor – Fits Mercury, Tohatsu, Nissan 2-6 HP Outboards provides a reliable, direct-fit solution for various Mercury, Mariner, Tohatsu, and Nissan 4-stroke outboard engines. It is engineered to restore proper air-fuel mixture, ensuring smooth idling, efficient combustion, and dependable engine performance across the 2 HP to 6 HP range.
It serves as a direct interchange for Mercury part numbers 853720T25 and 803819T03, as well as Tohatsu and Nissan equivalents 3R1-03200-1, 3AS-03200-0, and 3GV-03200-0.
- Installs as a direct OEM-style replacement with no modifications needed.
- Constructed from high-grade, machined aluminum alloy for durability and corrosion resistance.
- Designed to optimize air-fuel delivery for reliable engine operation.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number | Notes |
|---|---|---|
| Mercury / Mariner | 853720T25 | Also replaces 803819T03 |
| Tohatsu / Nissan | 3R1-03200-1 | Also replaces 3AS-03200-0, 3GV-03200-0 |
Engine & Model Compatibility
Confirm your engine model and horsepower in the table below. Note that year ranges are not available; verify fitment based on your engine's part number.
For Mercury & Mariner owners: This carburetor fits a range of 4-stroke models from 2 HP to 6 HP that use OEM part number 853720T25.
For Tohatsu & Nissan owners: This part is compatible with various 3.5 HP, 4 HP, and 5 HP 4-stroke models originally equipped with part number 3R1-03200-1.
| Brand | Model | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Mercury | Outboard | 2 HP | 4-Stroke | 853720T25 | Also replaces 803819T03 |
| Mercury | Outboard | 2.5 HP | 4-Stroke | 853720T25 | Also replaces 803819T03 |
| Mercury | Outboard | 3.5 HP | 4-Stroke | 853720T25 | Also replaces 803819T03 |
| Mercury | Outboard | 4 HP | 4-Stroke | 853720T25 | Also replaces 803819T03 |
| Mercury | Outboard | 5 HP | 4-Stroke | 853720T25 | Also replaces 803819T03 |
| Mercury | Outboard | 6 HP | 4-Stroke | 853720T25 | Also replaces 803819T03 |
| Tohatsu | MF3.5 | 3.5 HP | 4-Stroke | 3R1-03200-1 | Also replaces 3AS-03200-0, 3GV-03200-0 |
| Tohatsu | MFS4 | 4 HP | 4-Stroke | 3R1-03200-1 | Also replaces 3AS-03200-0, 3GV-03200-0 |
| Tohatsu | MFS5 | 5 HP | 4-Stroke | 3R1-03200-1 | Also replaces 3AS-03200-0, 3GV-03200-0 |
| Nissan | NFS4 | 4 HP | 4-Stroke | 3R1-03200-1 | Also replaces 3AS-03200-0, 3GV-03200-0 |
| Nissan | NFS5 | 5 HP | 4-Stroke | 3R1-03200-1 | Also replaces 3AS-03200-0, 3GV-03200-0 |
Technical Specs
- Product Type
- Carburetor
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Connection
- Direct mount
- Housing Material
- Aluminum alloy (machined)
- Housing Color
- Silver/metallic
- Fitting Type
- OEM replacement
- Key Feature
- Designed for precise air-fuel mixture for smooth combustion and reliable operation
What’s in the Box
- 1 x Carburetor (Replaces 3R1-03200-1 / 853720T25)
Installation Notes
- Ensure the engine is off and cool. Disconnect the fuel line and battery for safety.
- Remove the engine cowling to access the carburetor. Photograph or label all hose and linkage locations before removal.
- Carefully disconnect the throttle cable, choke linkage, and fuel hoses from the old carburetor.
- Unbolt and remove the carburetor from the intake manifold. Remove the old gasket and clean the mounting surface.
- Mount the new carburetor with a new gasket (not included). Hand-tighten the mounting bolts evenly.
- Reconnect all hoses and linkages, ensuring the throttle and choke move freely without binding.
- Reconnect the fuel line and prime the fuel system. Inspect thoroughly for leaks before starting the engine.
Troubleshooting & FAQ
How do I know if my carburetor is failing?
Common signs of a bad carburetor include difficulty starting the engine, rough or unstable idling, stalling at low speeds, black smoke from the exhaust, and fuel leaking from the unit itself. Poor acceleration or a sudden decrease in fuel efficiency are also strong indicators.
Does this carburetor need adjustment after installation?
This carburetor is pre-adjusted at the factory to match OEM specifications. However, minor adjustments to the idle speed screw may be necessary to achieve the perfect idle for your specific engine and local conditions.
Is a new gasket included with this part?
The package contains the carburetor assembly only. The mounting gasket is not included and should be purchased separately if your old one is worn, cracked, or damaged.
Will this fit my 2-stroke outboard model?
No. This carburetor is specifically designed for the 4-stroke Mercury, Mariner, Tohatsu, and Nissan engine models listed in the compatibility table. It is not compatible with 2-stroke engines.
How can I prevent fuel system problems in the future?
To maintain carburetor health, use fresh, high-quality fuel and add a marine fuel stabilizer during storage. Regularly check and replace your fuel filter, and avoid letting old fuel sit in the engine for extended periods.
What is the difference between an OEM and an aftermarket part?
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.
How fast is shipping and what does it cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
What is the warranty and return policy?
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 and specifications against your original part before purchase. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an OEM component.
- Professional installation is recommended for safety and optimal performance.
About Sea Sierra
- Pro-Grade Standards: We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.
- Fast Global Fulfillment: Enjoy free standard delivery to most regions, typically arriving in 5–15 days.
- Manufacturer-Direct Value: Our direct sourcing model ensures fair pricing without compromising on materials or quality control.
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