Carburetor – Fits Mercury Mariner 10HP 15HP 20HP 4-stroke (Replaces 853720T14, 853720T15, 853720T19, 853720T21, 8M0109535)

Product Details

This Carburetor – Fits Mercury Mariner 10HP 15HP 20HP 4-stroke is designed for Mercury Mariner outboard engines rated 15HP–20HP with 4-stroke, 2-cylinder configuration. Engineered to deliver reliable fuel metering for remote-control models with serial numbers 0R235168 through 0R833819 (carburetor serial 0R686020 and below).

Direct replacement for OEM part numbers 853720T14, 853720T15, 853720T19, 853720T21, and 8M0109535.

• Complete carburetor assembly ready for installation
• Compatible with remote-control Mercury Mariner 4-stroke outboards
• Fits 2-cylinder engines in the 10HP–20HP range

Part Number Matrix

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

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Technical Specs

Type

Carburetor Assembly

Application

Mercury Mariner 4-stroke outboard engines

HP Range

10HP, 15HP, 20HP

Stroke

4-Stroke

Cylinder Configuration

2-Cylinder

Control Type

Remote models

OEM Equivalent

853720T15, 853720T21, 8M0109535

What's in the Box

• 1 × Carburetor 853720T15

Installation Notes

1. Disconnect the battery and fuel line before beginning work.
2. Remove the engine cover and locate the existing carburetor assembly.
3. Disconnect the throttle linkage, choke cable, and fuel supply line from the old carburetor.
4. Unbolt the carburetor from the intake manifold using the appropriate socket or wrench.
5. Inspect the intake manifold gasket and replace if damaged or worn.
6. Position the new carburetor onto the manifold, ensuring proper alignment of mounting holes.
7. Secure with bolts and tighten evenly in a criss-cross pattern to the manufacturer's torque specification.
8. Reconnect the fuel line, throttle linkage, and choke cable in reverse order of removal.
9. Double-check all connections for tightness and proper routing.
10. Reconnect the battery and perform a fuel system prime if equipped with a primer bulb.
11. Start the engine and allow it to idle, checking for fuel leaks and smooth operation.
12. Adjust idle speed and mixture settings as needed per the engine service manual.

Troubleshooting & FAQ

How do I confirm this carburetor fits my engine?

Cross-reference your engine's serial number with the compatibility table above. Check the carburetor serial plate on your current unit; it should be 0R686020 or below. If your engine falls within the 0R235168–0R833819 range and is a 4-stroke 2-cylinder remote model rated 10HP–20HP, this carburetor is a direct fit.

What are the signs my carburetor needs replacement?

Common symptoms include rough idling, difficulty starting, poor acceleration, black smoke from the exhaust, fuel leaks around the carburetor body, or an engine that stalls frequently. If cleaning and rebuilding the existing carburetor does not resolve these issues, replacement is recommended.

Can I use this on a tiller-handle Mercury?

This carburetor is specified for remote-control models. Tiller-handle variants may have different throttle linkage configurations or fuel delivery systems. Verify your engine's catalog number and carburetor serial before ordering.

Do I need to adjust the carburetor after installation?

Yes, most carburetors require idle speed and mixture adjustments after installation. Consult your Mercury service manual for the correct procedure and specification values. Fine-tuning ensures optimal fuel efficiency and engine performance.

What is the difference between the various OEM part numbers listed?

The part numbers 853720T14, 853720T15, 853720T19, 853720T21, and 8M0109535 represent different production batches or supersessions by Mercury. All are functionally interchangeable for the engines listed in the compatibility table.

Will this work with ethanol-blended fuel?

This carburetor is designed to handle modern fuel formulations, including ethanol blends up to E10. For best results, use fresh fuel, add a marine-grade fuel stabilizer, and drain the carburetor if storing the engine for extended periods.

Safety & Important Info

• Verify images/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.