Most of us know that the primary purpose of a lawn mower gas cap is to keep the gas contained in the gas tank. As we indicated in one of our previous articles, a gas cap is necessary to avoid gas spilling over the yard. So, why do lawn mower gas caps have holes if their purpose is to keep the gas in the tank?
The holes in a lawn mower gas cap are there as vent to allow air to get into the tank. This air is important as the fuel level decreases because a vacuum can occur inside the tank. This vacuum won’t allow the gas to travel to the carburetor. As you likely guessed, the lawn mower will stop running if the carburetor is not getting fuel.
Clogged gas cap holes may be the culprit for a stalling lawn mower. To test your gas cap, you can loosen it to allow air into the tank to see if the lawn mower no longer stalls when operated. If you find that the gas cap is causing problem your mower to run improperly, you can replace it for around $5.00.