i have a hp500 carb motor. I had a issue with the motor cutin out at upper rpm for a split second. only did it above 4800. Today it did it and the motor died and i lost all power. The 90 amp fuse on the starter blew. Replaced it and it blew as soon as battery was turned on (key was off and nothing else on). So i took it out and connected wires straight to starter, When the battery is turned on it pops the 50 amp breaker. Anybody have any suggestions on what and how to check?