594605 594603 Carburetor Replacement for 17.5 14Hp - 18Hp Engine, Replacement for 796110 844717 591734 Riding Lawn Mower Carb Fits Nikki Carb Assembly Kit

What It Is

This is an aftermarket carburetor assembly kit designed to replace the Nikki carburetor on riding lawn mowers with 17.5 to 18 horsepower single-cylinder engines (typically Briggs & Stratton). It includes the carburetor body, gaskets, and related hardware, intended for restoring fuel delivery in mowers that run rough, stall, or won’t start.

Fitment & Compatibility

Check these before buying:

• Engine specs: Fits 17.5 HP and 14–18 HP Briggs & Stratton engines (e.g., 31C707, 31P977, 44N877). Verify your engine model number stamped on the valve cover or blower housing.
• OEM cross-references: Replaces original part numbers 594605, 594603, 796110, 844717, and 591734. If your old carb is one of these, this fits.
• Machine brand: Compatible with riding mowers from John Deere, Craftsman, Husqvarna, Troy-Bilt, and others using these engines. Not universal—confirm your engine model first.
• Measurements: Intake flange width is about 2.25 inches; fuel inlet is a standard 1/4-inch barb. Compare to your old carb or measure the mounting holes.
• Deck size irrelevant: This part doesn’t depend on deck width—only engine compatibility matters.

Key Things to Know

• Quality: Aftermarket, not OEM. May need slight adjustments (e.g., idle mixture screw) to run perfectly. Most users report it works fine out of the box, but some require cleaning or gasket trimming.
• Installation difficulty: Moderate. Requires removing the old carb, cleaning the intake, and attaching fuel and throttle linkages. Have basic tools (screwdrivers, socket set) and a clean workspace.
• Common gotchas: The included gaskets may be thin—use a bit of gasket sealer if you see leaks. Also, the fuel bowl drain screw can be tight; don’t overtighten to avoid stripping.
• Check for debris: Old fuel lines or tank sediment can clog the new carb. Replace the fuel filter and clean the tank if needed.

Should You Buy It

Buy this if your riding mower has a Briggs & Stratton 17.5–18 HP engine and you’re comfortable with basic mechanical work to save money over an OEM carb. It’s a solid budget fix for stalling or hard-starting issues—but skip it if you prefer a guaranteed drop-in replacement or your engine model isn’t listed.