Dad's been having trouble with his motor for a while now. He had the carb's rebuilt and cleaned and also replaced his fuel tank and houses with new parts. Yesterday he took it out fishing for the first time since getting this done. The motor fired up good at first, but wanted to die out when he would give it throttle so he had to choke it. Well after he was done fishing for the night, he came back but had trouble getting it to start and keeping the motor running. Now this morning he hooked the muffs to it and it won't even try to start. This is the same trouble had before he had the carbs rebuilt and replaced the fuel stuff. He's had it at two different mechanics and they still haven't gotten the issue resolved and he's getting very disgruntled with his motor. Any idea's what the problem could be?