Why can't I push the primer bulb in ? It's full of fuel, if I take fuel line off its fine. Took carb apart several times to clean. Bulb will push twice, fuel comes through and it will start and shut down immediately. I know several people had same problem. They bought a new carb. I'm not. This should be a recall on these. The carbs are a big problem. This is on a bolens hand tiller. Please. Help. Thanks