How to Replace a Primer Bulb on a Small Engine

Disconnect the spark plug wire. Let the engine cool if recently used.

Locate the primer bulb — a small rubber button usually on the air filter cover or carburetor housing.

Note how the current bulb is installed. Some snap in from the front, others are secured from behind with a retaining ring.

For snap-in style: use a flat screwdriver to pry the old bulb out from the front. It may be brittle and crack — that's fine.

For retaining ring style: remove the retaining ring from behind (inside the housing) with needle-nose pliers, then push the bulb out.

Clean the mounting hole of any debris or old rubber fragments.

Install the new primer bulb. For snap-in: press firmly from the front until it clicks into place. For retaining ring: insert from the front and secure the ring from behind.

Test by pressing the bulb several times. It should feel firm and spring back. You should see fuel moving through the clear fuel line if equipped.

If the primer still doesn't draw fuel, the issue may be cracked fuel lines or a clogged carburetor, not just the bulb.