799583 Carburetor Kit for B&S 593261 595656 591979 591160 590556 591109 594058 300E 450E 500E 550E 550EX 125cc 140cc Lawn Mower Engines with 799579 Filter 595660 Cover

What It Is

This is a complete carburetor replacement kit for Briggs & Stratton single-cylinder engines (125cc and 140cc), commonly found on push mowers like the 300E, 450E, 500E, 550E, and 550EX series. It includes the carburetor, gaskets, fuel filter (799579), and air filter cover (595660), so you can refresh the entire fuel system in one purchase.

Fitment & Compatibility

Before buying, confirm your engine’s type number (e.g., 593261, 595656, 591979, 591160, 590556, 591109, 594058) – this is stamped on the blower housing or valve cover. This kit replaces OEM part 799583 and fits B&S engines with plastic carburetors (not metal). It will not fit larger engines (190cc+) or models with a primer bulb on the carb. Check that your air filter cover is the rectangular, side-mount style (not round or top-mount). Deck size is irrelevant – only engine model matters.

Key Things to Know

• Quality: Aftermarket, not OEM. Gaskets and seals are adequate but may be slightly thinner than originals. The included fuel filter (799579) is a direct fit.
• Installation: Moderate difficulty. You’ll need to remove the old carb, swap the throttle/governor linkage, and transfer the primer bulb (if present). Watch for small springs – they’re easy to lose.
• Common gotchas: The air filter cover (595660) may be a tight snap on older engines. If your engine uses a fixed-jet carb (no adjustable needle), this kit is correct; if it has an adjustable main jet, this won’t work.
• Performance: Expect it to run well after a brief break-in period. Some users report needing to clean the new carb’s internal passages with compressed air before install.

Should You Buy It

If your B&S 125cc–140cc engine is surging, hard-starting, or won’t run, and you’re comfortable swapping a carb in under an hour, this kit is a solid value at $18. It’s not for pro-grade longevity, but for a homeowner mower, it’s a cheap fix that usually works. Skip it if you need OEM exactness or have a metal-carb engine.