498751 Carburetor For Nikki 498751 266-091 266-2408 Compatible with Briggs Stratton 20Hp 21HP V-Twin Intek Engines With Air Filter

What It Is

This is a complete aftermarket carburetor assembly designed to replace the Nikki 498751 unit on Briggs & Stratton 20hp and 21hp V-Twin Intek engines. It includes the air filter, making it a direct bolt-on for mowers, tractors, and zero-turns using those engines.

Fitment & Compatibility

• Engine models: Briggs & Stratton V-Twin Intek with 20hp or 21hp (typically 40T7, 44N7, or similar codes). Check your engine’s model/type/spec numbers on the valve cover or blower housing.
• OEM cross-references: Replaces Nikki 498751, Briggs 266-091, and 266-2408. Confirm your current carburetor’s stamped numbers match.
• Deck size not relevant – fitment depends only on engine model, not mower deck width.
• Physical check: Measure mounting bolt spacing (approx. 3.25” center-to-center) and intake port diameter (about 1.25”). Ensure your fuel line and choke cable connect without modification.
• Air filter included – verify that the filter shape matches your existing air cleaner housing (some Intek models use a different filter base).

Key Things to Know

• Aftermarket quality: This is a non-OEM carburetor. While functional, it may require minor adjustment of the idle mixture screw (if adjustable) and throttle linkage fine-tuning for smooth operation.
• Installation difficulty: Moderate. You’ll need basic hand tools, a new gasket (often included), and patience to bleed air from the fuel system. Expect 30–60 minutes.
• Common gotchas:
  • The included air filter may be slightly smaller than OEM – check fitment in your housing before final assembly.
  • Old fuel lines can be brittle; replace them if cracked to prevent air leaks.
  • Some units ship with a plastic float that can stick if debris enters – install an inline fuel filter if one isn’t present.
• Warranty: Check the seller’s return policy; aftermarket carbs often have limited support.

Should You Buy It

If your Briggs Intek V-Twin’s original carburetor is clogged, leaking, or beyond cleaning, this is a cost-effective replacement. It’s best for DIYers comfortable with basic engine work and willing to make small adjustments. For professional or high-hour use, an OEM carburetor may offer better long-term reliability.