My 1979 Everest 340 isn't running to good. It will only start on a prime, even when the engine is warm. When I first start it, it revs real high, then dies. The timing seems good, I'm getting spark in both cylinders. I've checked the carb. It seems fine. It seems the engine is starving for gas, or is extremely lean. Would this be a sympton of a blown crank seal? This summer I replaced the two end seals on the end of the crank and the O-rings on the crank.