796109 594593 Carburetor Replacement for Briggs Stratton 591731 594593 792171 792358 793224 17.5Hp 18Hp 18.5Hp 19Hp 20Hp 21Hp Engines

What It Is

This is an aftermarket carburetor replacement for Briggs & Stratton single-cylinder engines in the 17.5 to 21 HP range, commonly used on riding mowers, lawn tractors, and zero-turn mowers. It replaces OEM part numbers 591731, 594593, 792171, 792358, and 793224.

Fitment & Compatibility

Before buying, confirm your engine model number (found on the valve cover or blower housing) and check that it matches one of the listed OEM numbers. This carb fits Briggs engines with a horizontal shaft and a fixed-jet carburetor design—most commonly the 31, 33, 40, 44, and 49 series. It will not fit vertical shaft engines or engines with a different mounting pattern. Measure your carb mounting bolt spacing (typically 2.5 inches center-to-center) and compare to your old unit. Also verify your air filter and fuel line sizes (usually 1/4 inch) to avoid needing extra adapters.

Key Things to Know

• Quality varies – This is a budget aftermarket part; some units may have debris in the fuel bowl or rough gaskets. Inspect and clean before install.
• Installation difficulty – Moderate. You’ll need basic tools (screwdrivers, socket set) and patience with linkage alignment. Expect 30–60 minutes.
• Tuning required – After install, you may need to adjust the idle and mixture screws (if adjustable) to prevent surging or stalling.
• Gasket fit – The included gaskets are often thin and may leak. Using a thin layer of gasket sealant or replacing with OEM gaskets is recommended.

Should You Buy It

Buy this if you’re on a tight budget and comfortable with minor adjustments and cleaning out a new part. It’s a functional fix for a non-running mower, but if you want plug-and-play reliability or have a critical commercial machine, spend more on an OEM carburetor.