799585 799684 Fuel Tank Cap for B&S Mower 550E & 550EX, 625E, 675EX & 725EX Series and Professional Series 7.75-8.75 Engines Replacement, 2 Pack Gas Cap for Lawn Mower

What It Is

This is a replacement fuel tank cap designed for select Briggs & Stratton engines used on push mowers and small riding mowers. It seals the gas tank to prevent leaks and debris entry, and includes a vent to allow proper fuel flow.

Fitment & Compatibility

Before buying, verify your engine model. This 2-pack fits B&S 550E, 550EX, 625E, 675EX, and 725EX series, plus Professional Series 7.75–8.75 engines. It replaces OEM part numbers 799585 and 799684. Check your cap’s diameter and thread pattern—these caps fit standard 1.25-inch threaded filler necks. If your mower uses a non-vented cap or a different thread, this won’t work. Measure your old cap or look up your engine’s spec sheet.

Key Things to Know

• Quality concerns: With a 3.4 rating from only 3 reviews, consistency is unproven. Some users report loose fit or poor venting.
• Installation: Simple twist-on, no tools needed. Ensure the cap seals tightly to avoid fuel evaporation or leaks.
• Venting: If your engine runs rough or stalls after replacing, the cap may not vent properly. Test by loosening it slightly—if it runs better, the cap is faulty.
• Two-pack value: At $11.99, it’s cheap per cap, but you may only need one. Keep the spare for future use.

Should You Buy It

Buy this only if you have a confirmed B&S 550E–725EX or Professional Series engine and need a cheap, quick fix for a lost or cracked cap. If you want reliable venting and long-term durability, look for an OEM cap or a higher-rated aftermarket option—this one is a gamble.