Set of 2, 694395 4180 Primer Bulb Replacement for Briggs & Stratton 496115 4180 5085 5085H 5085K Lawn Mowers

What It Is

This is a set of two replacement primer bulbs (model 694395/4180) for Briggs & Stratton engines that use a push-button primer bulb to manually feed fuel into the carburetor before starting. Common on walk-behind mowers, tractors, and small engines where the primer bulb has cracked, hardened, or won’t seal.

Fitment & Compatibility

• Direct OEM replacements for Briggs & Stratton part numbers 496115, 4180, 5085, 5085H, and 5085K.
• Verify your engine model number (stamped on the valve cover or blower housing) matches one of these OEM numbers.
• Not universal – check the bulb diameter (typically ~1 inch) and stem length. Measure your old bulb’s stem length and base diameter to confirm.
• Works on most Briggs & Stratton engines with a plastic carburetor and push-in primer bulb design (common on Series 450, 500, 550, 575, 625, 675, 725, 775). Not for metal carburetors or screw-in bulbs.
• Aftermarket set, not genuine Briggs & Stratton – usually fine, but inspect for flashing or rough edges before install.

Key Things to Know

• Installation is simple – pop out the old bulb (may need a small flathead screwdriver), push the new one into the carburetor hole until it snaps in. No tools required.
• Check for cracks – old bulbs often fail from UV exposure and fuel vapors. If the bulb feels hard or has a white haze, replace immediately.
• Primer bulb must seal tightly – if air leaks, the engine won’t start. After installing, press the bulb 3-4 times and watch for fuel in the bulb. If it doesn’t stay firm, the bulb or carburetor gasket may be bad.
• Common gotcha – some aftermarket bulbs are slightly stiffer than OEM. They work, but may require a firmer push. If the bulb won’t snap in, lightly sand the stem edges with fine grit sandpaper.

Should You Buy It

If your Briggs & Stratton engine won’t start or needs multiple primer pumps, and the bulb is cracked or hard, this $6.29 set is a cheap, easy fix. Works well for most push mowers and small tractors with the listed OEM numbers. Skip if you have a metal carburetor or a screw-in primer design – those need a different part.