Does this mean that I definitely have a messed up valve, or could it be that one of my guys put too much oil in the mix? I have tried running it out but it keeps coming. A lot of times I can't get it to start but when I do I can keep it running for up to 60-90 seconds, then it shuts off (after spitting out oil onto the ground). Any ideas would be appreciated. Thanks! Also, I have cleaned the carb once, poured out old gas and removed the spark arrestor.