Try a use a different lipo since yours is probably damaged internally.
The motor normally gets hot during operation, but you shouldn't find that it's hot on the pistol grip.
Otherwise check the wiring.
The lonex also uses metal brush hood screws, but I think it has a plastic retaining ring, so that shouldn't be an issue.
And check the resistance on the wiring when the mechbox is in the gun, I've had shorts ground through the receiver before.