1. Clean and refill the lawn mower fuel tank. An obvious—and often overlooked—reason your mower is not starting is that the tank is empty or contains gas that is either old or contaminated ...

5. Clean and refill the lawn mower fuel tank. 5. Clean and refill the lawn mower fuel tank. If your gas is more than a month old, use an oil siphon pump to drain it from the tank. If your gas is ...