799585 Fuel Tank Gas Cap, Fit for B&S 550E 550EX 625E 675EX 725EX Series, 7.75-8.75 Professional Series Engines, T royBilt 200 100 Mower, Gas Tank Caps Replaces 799684/591003, 2 Pack

What It Is

This 2-pack gas cap (part 799585) seals the fuel tank on specific Briggs & Stratton 550E, 550EX, 625E, 675EX, 725EX, and Professional Series 7.75–8.75 engines, as well as Troy-Bilt 200/100 mowers. It replaces OEM caps 799684 and 591003.

Fitment & Compatibility

• Engine series confirmed: B&S 550E, 550EX, 625E, 675EX, 725EX, and Professional Series 7.75–8.75.
• Mower brands: Works on Troy-Bilt 200 and 100 series; also fits many MTD, Cub Cadet, Craftsman, and Husqvarna models using these engines.
• Check before buying:
  • Measure your cap’s outer diameter (should be ~1.5 inches) and thread pitch (standard 2-3/8″-6).
  • Verify your engine model number (stamped on valve cover or blower housing) ends in the series listed above.
  • Not compatible with OHV, Intek, or Vanguard engines unless specifically cross-referenced.
  • Does not include a tether or vent valve; ensure your tank neck is clean before installing.

Key Things to Know

• Quality: Plastic construction is adequate but not heavy-duty; some users report cracking after 1–2 seasons in direct sun.
• Installation: Hand-tighten only—overtightening can strip threads or crack the cap.
• Venting: This cap is non-vented (sealed). If your mower has a separate vent line, it’s fine. If your original cap had a built-in vent, this won’t work and may cause vapor lock.
• 2-pack value: Good for backup or for two identical mowers, but check that both caps fit your tank—some users report slight variations in thread depth.

Should You Buy It

Buy this if you need a direct replacement for a B&S 550E–725EX or Troy-Bilt 200/100 mower, want a spare on hand, and your original cap is non-vented. Skip it if your engine requires a vented cap or if you need a metal, UV-resistant part for heavy commercial use.