Carburetor for Briggs & Stratton 594593 591731 796109 796078 590400 31H777 Models Engine, Carb with Tune-Up Kit Replaces for Craftsman LT1000

What It Is

This is a complete carburetor assembly with a tune-up kit (spark plug, air filter, fuel filter) designed for Briggs & Stratton engines, commonly used on Craftsman LT1000 lawn tractors and similar riding mowers.

Fitment & Compatibility

Before buying, confirm your engine model number (not just mower brand). This carb fits Briggs & Stratton part numbers 594593, 591731, 796109, 796078, and 590400. It’s specifically for 31H777 engine models (find the code stamped on the valve cover or blower housing). Works with Craftsman LT1000, but also many other brands using these engines—check your deck size isn’t the only identifier. This is an aftermarket replacement, not OEM Briggs. Measure your carb mounting stud spacing (typically 3.5 inches center-to-center) and ensure the bowl drain screw matches your setup.

Key Things to Know

• Quality variance: Aftermarket carb may need minor adjustments (idle speed screw, float height) out of the box. Some users report needing to clean debris from jets before install.
• Installation difficulty: Moderate. Expect 30-60 minutes. You’ll need basic tools (socket set, screwdrivers), and careful gasket alignment to avoid vacuum leaks.
• Tune-up kit included: The spark plug, air filter, and fuel filter are generic—verify they match your specific engine air box and plug gap (usually 0.030 in). Replace fuel lines if old.
• Common gotcha: Old gasket residue on the intake manifold must be fully removed. Use a new gasket from the kit; don’t reuse the old one.

Should You Buy It

If your Briggs 31H777 engine runs rough, won’t start, or floods, this is a budget-friendly fix. It’s ideal for DIYers comfortable with basic carb work who want a complete service kit in one purchase. Not for those needing OEM exactness or professional-grade durability—expect to tweak settings for best performance.