594593 Carburetor for Briggs and Stratton 697141 697190 791858 791888 792171 792358 Lawn Tractor 17HP 19HP 21HP Engine 31G777 31N707 31P677 31P777 Carb

What It Is

This is an aftermarket carburetor designed to replace the OEM unit on single-cylinder Briggs & Stratton engines used in lawn tractors, specifically models like the 31G777, 31N707, 31P677, and 31P777. It supports 17HP, 19HP, and 21HP engines, making it a direct swap for mowers that have lost their prime or run poorly due to clogged jets or worn gaskets.

Fitment & Compatibility

Before buying, verify your engine’s model number (e.g., 31G777, 31N707) – it’s stamped on the valve cover or blower housing. This carb replaces OEM part numbers 697141, 697190, 791858, 791888, 792171, and 792358. It fits most Briggs & Stratton Intek and similar single-cylinder engines from the early 2000s onward. Check your old carb’s mounting pattern (two-bolt flange) and fuel line diameter (typically 1/4-inch). It does not fit V-twin engines or older cast-iron Briggs models. Measure your carb’s body width and bolt spacing to confirm.

Key Things to Know

• Quality variance: This is an aftermarket part, not OEM. Some users report needing to clean out debris or adjust the float height out of the box.
• Installation difficulty: Moderate. Expect to remove the air filter, fuel line, and throttle/governor linkages. A small screwdriver set and needle-nose pliers help. Watch a video guide for your specific engine model.
• Common gotcha: The gaskets included may be slightly thicker or thinner than OEM. Use the old gasket as a template, and always check for vacuum leaks after installation (spray carb cleaner around the base – idle change means a leak).
• Tuning required: After installing, you may need to adjust the idle speed and mixture screws (if present) to prevent surging or stalling. Start with 1.5 turns out on each screw.

Should You Buy It

If your tractor’s engine is hard-starting, backfiring, or flooding, and you’re comfortable with basic small-engine wrenching, this $17.90 carb is a cost-effective fix. It’s ideal for budget-conscious DIYers who don’t mind minor adjustments. If you want a guaranteed no-hassle swap or have a high-hour engine with other issues (worn rings, valve problems), stick with an OEM carb or rebuild the original.