Hey everyone been a while since I've been on. Hope everyone is good. Got a new project a 88 37 foot coachman classic motorhome with 350 tbi. Runs and drives. Drove it home has sat for 2 yrs. But now when I hit the key it makes a thunk noise. I can see the belt try to move and the fan kinda spin not sure if it's not getting enough juice to turn over or it has bad ground or what could be causing it not to turn over. If any ideas much appreciated thanks