I had the same problem with mine when I first got it, there didn't seem to be enough compression in my engine to run the fuel through the fuel lines, took it to the service guy in my town and he looked at it and took my carburetor off. I'm not sure on exactly what he done but i Know he adjusted my carburetor in some way. Just figured i'd throw it out there since that's what I had to do with mine and now everytime I try to prime it, it works first shot.