Briggs & Stratton 594281 Primer Bulb

What It Is

This is a genuine OEM replacement primer bulb for Briggs & Stratton engines, used to manually push fuel into the carburetor for easier cold starts. It fits many walk-behind mowers, tractors, and small engines with compatible carburetors.

Fitment & Compatibility

Before buying, confirm your engine model number (located on the valve cover or blower housing). This bulb fits most Briggs engines with a 3/4-inch diameter mounting hole and a center stem height of about 1 inch. It replaces part numbers 594281, 691158, and 80003772. Check that your carburetor uses a push-in type bulb (not a screw-in or twist-lock). For non-Briggs engines, measure your existing bulb’s stem diameter and hole size—aftermarket alternatives may be needed if dimensions differ.

Key Things to Know

• Quality: OEM part; matches factory fit and durability. Cheaper aftermarket bulbs may crack or leak after a season.
• Installation: Simple—pull out the old bulb (use needle-nose pliers if stuck), press the new one in until seated. No tools required.
• Common gotcha: If the primer bulb is stiff or hard to push, the carburetor may have a clogged fuel line or a bad check valve—replacing the bulb alone won’t fix that.
• Spare tip: Keep a spare on hand; they’re cheap and fail most often from UV damage or ethanol fuel.

Should You Buy It

If your Briggs engine’s primer bulb is cracked, hard, or won’t hold prime, this OEM replacement is the right call. It’s a quick, low-cost fix for hard starting, but only buy it if you’ve verified fitment and ruled out other fuel system issues.