498751 Carburetor For Nikki 498751 266-091 266-2408 Replaces Briggs Stratton 20Hp 21HP V-Twin Intek Engine With Fuel Pump

What It Is

This is a complete aftermarket carburetor assembly for Briggs & Stratton V-Twin Intek engines (20HP–21HP) that includes an integrated fuel pump. It replaces OEM part numbers 498751, 266-091, and 266-2408, designed for riding mowers, zero-turns, and garden tractors.

Fitment & Compatibility

Before buying, confirm all three:

• Engine model: Fits Briggs & Stratton V-Twin Intek models (e.g., 40H777, 40P777, 44N777) with 20–21HP.
• OEM part cross-reference: Directly replaces Briggs parts 498751, 266-091, 266-2408.
• Physical check: Measure your old carburetor’s mounting bolt spacing (center-to-center, typically 2.5″). Verify fuel inlet orientation and bowl size match your engine’s air filter housing.

Does not fit: Single-cylinder engines, older opposed-twin Briggs, or Kawasaki/Kohler engines. Not compatible with engines that have a separate external fuel pump.

Key Things to Know

• Integrated fuel pump: This carb has a built-in pulse-operated pump—no separate pump needed. Ensure your engine has a pulse line (usually from crankcase breather) and that it’s not blocked.
• Installation difficulty: Moderate. Expect to remove the air filter housing, old carb, and gaskets. You’ll need a new gasket (often included) and may need to adjust idle/mixture screws (typically 1.5 turns out as baseline).
• Common gotcha: The included fuel pump diaphragm may be stiff initially; cycle the engine a few times to prime. If engine starts then dies, check for a clogged pulse line or a misaligned gasket blocking fuel flow.
• Quality note: Aftermarket carburetors can vary—this one has solid reviews (4.8/5, 13 ratings) but is not OEM. Expect plastic components that may be less durable than original metal parts.

Should You Buy It

If you have a Briggs V-Twin Intek that won’t start or runs poorly due to a clogged or failed carb, this is a cost-effective replacement. It’s ideal for DIY repairs on older riders or tractors where OEM parts are expensive or backordered. Avoid if you need exact OEM fitment or have a newer engine with electronic fuel management.