My starter just turns real slow and wont engage what can I do?

ok so im finally done building my mower and once im done i cant get my motor to start. so i decided to jump it right off the starter. the starter just turns real slow and wont engage. well once it does engage it turns it real slow or not at all. i dont have a ground from the motor but i never have. i noticed that the spring for my throttle which goes from the throttle body straight to the frame was getting super hot. also it looks like some wires are coming out of my magneto could all this amount to a problem and should i run a ground. if you need any specific details just ask thanks

I always ground the engine, paint on the frame does not lend itself to a good ground so the engine mount bolts don't always give a good ground.

ok thanks