my god. . . there were only 2-3 guys that gave you the correct advice. it's 1
of 2 things, the unloader as they suggested is bad or if the check valve is
not seating , air will be allowed to flow back into the cylinder thus giving
the moter a much larger initial load at start up. Do these couple of checks:
1st start compressor and when it reaches it's cut off pressure and stops,
loosen the fitting on the steel line going from cylinder to tank. loosen at the
cylinder. you should be able to remove the fitting completely w/ out hearing
any hissing. IF it hisses, check valve is bad. No hiss = bad unloader, located
by your pressure sw. let me know what you find , but theres a 99.9 % chance
iit's 1 of those 2 things.