I have a 76' 85hp johnson motor that has been sitting up for 2 years in a shed. Ran perfect last use and ran it out of gas before storing. Tried to run motor and while cranking, the positive cable hooked up to the battery melted the lead post of the battery. What in the heck would cause this? Is there anything that I should do to the motor since it sat for so long? All wiring looks good and motor only had dust on the outside. Very clean on inside.