591731 594593 Carburetor for Brigg Stratten 17.5HP 796109 31H777 31C707 31P777 594601 795477 799727 699915 794572 590400 697109 for 14.5HP 18Hp Engines Lawn Mower Tractor Nikki Carb Craftsman lt2000

What It Is

This is an aftermarket Nikki-style carburetor designed to replace the OEM carb on Briggs & Stratton 17.5HP and 14.5HP single-cylinder engines commonly used in Craftsman LT2000, LT1000, and similar lawn tractor models. It handles fuel mixing and delivery to the engine, often a direct fix for surging, hard-starting, or no-start conditions caused by a clogged or failed factory carb.

Fitment & Compatibility

Before buying, verify your engine model number (not just tractor model). This carb fits Briggs & Stratton engines with model numbers like 31H777, 31C707, 31P777, and others listed (e.g., 796109, 594601, 795477). Check the engine’s stamped metal shroud near the spark plug for the model/type/serial code. It replaces OEM part numbers 591731 and 594593. Works on 14.5HP and 18HP engines too (e.g., 590400, 697109). Does not fit V-twin or overhead valve (OHV) engines with different mounting patterns. Measure the carb mounting flange bolt spacing (typically 2.5 inches center-to-center) and the fuel inlet nipple diameter (usually 5/16-inch) to confirm. If your engine uses a different primer bulb or choke linkage, you may need to swap your old parts onto this carb.

Key Things to Know

• Quality varies: While rated 4.6/5, some users report gaskets that don’t seal perfectly or a slightly lean mixture out of the box. Consider cleaning any shipping debris and checking the float level before installing.
• Installation is straightforward but requires a few tools: a socket set, a small flathead screwdriver for the bowl screw, and possibly a fuel line clamp. Expect 30–60 minutes if you’re handy.
• Common gotcha: The included fuel line may be too short or slightly different diameter than your original. Reuse your existing hose if needed. Also, the choke linkage hole might need a minor ream for your cable to fit.
• Not a performance upgrade — it’s a direct replacement. If your engine runs fine but has other issues (valves, spark, compression), this won’t fix those.

Should You Buy It

If your Briggs & Stratton 17.5HP or 14.5HP engine is surging, hard to start, or won’t stay running, and you’ve confirmed the carburetor is the issue (clean fuel, good spark, no air leaks), this $16.23 aftermarket carb is a solid, low-risk fix. It’s ideal for DIYers who want a cheap, fast replacement over rebuilding the original Nikki unit. Skip it if you need OEM exactness for a commercial mower or if your engine model isn’t in the compatibility list.