Briggs & Stratton 842921 Oil Filter

What It Is

The Briggs & Stratton 842921 Oil Filter is a spin-on, full-flow filter designed for air-cooled engines found on walk-behind mowers, riding tractors, zero-turns, and other outdoor power equipment. It traps debris and contaminants to extend engine life, and is a direct OEM replacement for many Briggs & Stratton engines.

Fitment & Compatibility

Before buying, verify your engine’s model number (stamped on the valve cover or blower housing). The 842921 fits most Briggs & Stratton single- and twin-cylinder engines with a 3/4-16 threaded mounting base and a filter height of ~2.9 inches. It is not compatible with engines requiring a 1-inch thread or short filters (e.g., 492932). Cross-reference with OEM part numbers 842921, 698369, or 796979. Aftermarket equivalents (e.g., Champion CH312 or STP S14) exist, but the OEM version ensures exact seal and bypass specs. Measure the old filter’s diameter (approx. 2.9 in) and check your engine’s oil filter adapter fitment—some older models use a different base.

Key Things to Know

• Quality: OEM construction with a silicone anti-drainback valve and high-efficiency media; rated for 100 hours of use in standard conditions.
• Installation: Easy—hand-tighten only (1/2 to 3/4 turn after gasket contact). Overtightening can strip threads or damage the gasket.
• Gotcha: Do not use on engines with a remote filter mount unless the adapter matches the 3/4-16 thread. Always pre-fill the filter with oil before installation to prevent dry starts.
• Common issue: Some aftermarket filters may leak at the gasket if not torqued correctly; the OEM filter has a thicker gasket for better sealing.

Should You Buy It

If you own a Briggs & Stratton engine that calls for the 842921 (check your manual or existing filter), this is a reliable, easy-to-install OEM option that won’t void your warranty. It’s ideal for routine oil changes on mowers, tractors, and generators—especially if you want guaranteed fit and bypass valve performance. Skip it only if you’re on a tight budget and willing to cross-reference a quality aftermarket equivalent.