Report "It blows the circuit breaker switch on the unit. I can run it for 1 hour at 12 mph (no one on it) and it's just fine. I can get on it (190lbs) and within 3-4 minutes the circuit blows. Wife 115 lbs can run on it for 2 hours with no problem. I have replaced teh circuit breaker, adjusted belt (2-3" above deck) and lubricated belt. No success Any idea?"