Carburetor Carb Replaces For Briggs Stratton IC intek 13.5Hp 14Hp 14.5Hp 15Hp 16Hp 17Hp 17.5Hp 18Hp 20Hp 21Hp Engine 331877 31P977 799256 31S977 331707 331777 331807 331977 33R877 31P677 303777

What It Is

This is an aftermarket carburetor designed to replace the original equipment (OEM) carburetor on Briggs & Stratton single-cylinder Intek and IC engines ranging from 13.5 to 21 horsepower. It handles fuel metering and air/fuel mixing for engines used on walk-behind mowers, riding mowers, and garden tractors.

Fitment & Compatibility

Before buying, check these three things:

1. Engine model numbers – Your engine’s model, type, and code numbers (stamped on the valve cover or blower housing) must match one of these: 331877, 31P977, 799256, 31S977, 331707, 331777, 331807, 331977, 33R877, 31P677, 303777. This carburetor is not universal—it fits only the specific engine families listed.

2. OEM part numbers – It replaces Briggs & Stratton OEM numbers 594231, 593899, 591779, 591757, and 591351. If your current carburetor is one of those, this aftermarket unit is a direct swap.

3. Physical check – Measure the mounting flange bolt spacing (typically 2.75” center-to-center) and the fuel inlet fitting size (usually 5/16” or 1/4” barb). The throttle and choke linkage must match your engine’s orientation. If your engine has a plastic intake or a different fuel pump, this carb may not bolt up without modifications.

Note: This is an aftermarket part, not OEM. Expect minor differences in gasket thickness or needle seat quality.

Key Things to Know

• Installation difficulty: Moderate. You’ll need a socket set, screwdriver, and possibly a carburetor gasket kit. Expect 30–60 minutes if you’re comfortable with small engine fuel systems.
• Common gotchas: The fuel bowl gasket may be thin—replace it if it leaks. The main jet is pre-set; you cannot adjust idle mixture on most models. If the engine runs lean, check for vacuum leaks at the intake gasket.
• Quality: Mixed. Most buyers report it works out of the box, but a few receive units with debris in the bowl or a sticky float. Inspect and clean before installing.
• Fuel line compatibility: The inlet may be slightly different from OEM. You might need a new fuel line or a small adapter (often included in the box).

Should You Buy It

Buy this carburetor if you have a compatible Briggs & Stratton Intek/IC engine (13.5–21 HP) and want a budget fix for a clogged, worn, or non-rebuildable original carb. It’s a good value for DIYers who don’t mind minor adjustments and occasional quality checks. Skip it if you need an exact OEM replacement for a commercial-use mower or if your engine has a different model number not listed—those will require a different carb.