In my case, the contacts on the start switch needed cleaning.
Disassemble the starter switch housing (two screws). Then there are two smaller screws holding in the electric switch. Carefully take the switch apart as there are loose parts in there. There are a couple solid metal knobs in there that need cleaning. I sanded them lightly with some fine sand paper. Also, the top and bottom of the spring needed cleaning as well (since the spring is part of the circuit too). Motor started up no problem after I did this.
I was having problems starting the motor and in fact nothing was happening when I depressed the start switch. The battery was good. I could also jump the solenoid and start the motor. With some testing with my brother, using a multimeter, we found that the start switch was the culprit.
I made another post called something like "Solenoid only getting 3v" that forced me to find this solution that I'm posting here today.
