Fits Briggs and Stratton Fuel/Gas Cap 397974 397974S 692046 793606

What It Is

This is an aftermarket replacement fuel cap designed for Briggs & Stratton engines, commonly used on walk-behind mowers, riding mowers, and small outdoor power equipment. It replaces OEM part numbers 397974, 397974S, 692046, and 793606.

Fitment & Compatibility

Before buying, verify your mower’s engine model and serial number—this cap fits most Briggs & Stratton engines with a standard 1.5-inch twist-on fuel tank opening. Check your old cap’s part number stamped on the underside or side; if it matches one of the four listed, you’re good. Avoid assuming fit based on mower brand alone—this works with many Craftsman, Toro, Troy-Bilt, and MTD models, but only those using Briggs engines. Measure the cap’s outer diameter (about 1.75 inches) and thread pattern (standard coarse). If your cap is a push-on or vented differently, this won’t work.

Key Things to Know

• Quality: Aftermarket cap, not OEM. Most users report a snug fit, but a few note slight looseness on older tanks. Inspect for cracks or distortion before installing.
• Installation: Tool-free—just twist on until hand-tight. Over-tightening can strip threads or crack the cap.
• Venting: This cap is vented. If your engine runs rich or stalls after replacement, ensure the vent hole isn’t blocked (dirt or paint can clog it). A non-vented cap may cause vacuum lock.
• Common gotcha: On some Briggs tanks, the cap may not seal fully if the tank neck is warped or corroded. Clean the neck with a rag first; if it still leaks, the tank may need replacement.

Should You Buy It

If you need a quick, budget-friendly fix for a lost or damaged fuel cap on a Briggs-powered mower and you’ve confirmed the part number match, this is a solid choice. It’s not OEM, but for $12.92 and a 4.4-star rating, it’s reliable for most users. Skip it if you have a non-standard tank or want a guaranteed perfect seal on an older engine.