My son has an icebear 125 and when I start it the green ground wire casing starts to melt. Any suggestions?

 

I'm not sure what you mean by "green ground wire casing". But in any case when wiring melts it means one of two things:

1) Too much current passing through the joint - much more than it was designed to pass.

2) The connection is bad at the joint. Too much resistance is getting in the way of the current flow and the voltage drop is getting turned into heat.

If an entire wire gets hot end to end, or if multiple joints/connections along the same path all get hot then that points to #1 above. If only one joint/connection gets hot then that suggests #2 above.

I would bet you just a a bad connection that need to be reworked/replaced. This is especially so if it gets hot in only one place. Concentrate right there at the hot spot.