Gas Cap Assembly 951-10300 751-10300 for MTD 4.5-6.5 HP Engines

What It Is

This is a replacement gas cap assembly (models 951-10300 and 751-10300) for MTD lawn mowers and tractors with 4.5 to 6.5 HP engines. It seals the fuel tank, prevents leaks and evaporation, and includes the cap, tether, and vent mechanism.

Fitment & Compatibility

Before buying, verify these three things:

• Engine type: Fits MTD, Troy-Bilt, Cub Cadet, Yard Machines, and Yard-Man mowers with 4.5–6.5 HP engines (typically Briggs & Stratton or similar). Does not fit larger HP engines or non-MTD brands without adapter.
• OEM vs aftermarket: This is an aftermarket cap, not OEM MTD. It’s a direct replacement for OEM part numbers 951-10300 and 751-10300, but may have slight color or tether length differences.
• Measurements: Cap diameter is approximately 1.5 inches (38 mm). Check your tank opening—if it’s larger or smaller, this won’t seal. Also confirm the cap is vented (if your original had a vent hole) or non-vented (if your tank has a separate vent line).

Key Things to Know

• Quality: Solid build for the price—plastic cap with rubber gasket. A few users report the tether feels flimsy; handle gently when removing.
• Installation: Dead simple—unscrew old cap, screw on new one. No tools needed. Takes 30 seconds.
• Common gotcha: The vent may be too tight or too loose on some tanks. If you smell gas after install, the gasket isn’t seating—try tightening by hand or add a thin rubber washer.
• Fit note: Works on most MTD tanks, but some users report it’s slightly shallow for deeper filler necks. If your original cap was tall, this may sit lower.

Should You Buy It

Buy this if you need a cheap, functional replacement for a worn or lost gas cap on a standard MTD mower with a 4.5–6.5 HP engine. It’s not for high-end machines or those requiring an OEM exact match, but for the price, it seals well and gets the job done. Skip it if you need a vented cap for a tank with a separate vent line—double-check your setup first.