Hot jumper cable, what is the problem?

[potato124]

Hello,

I recently tried to start my 65 Corvair Monza 110, which had been sitting for over a month. It was turning over strong, but simply not starting. I tried a little gas in the carb, and still nothing. During the process, it was turning over slower and slower. Finally it wouldn't turn over, so I tried to jump start it. However, when it wouldn't turn over with the jumper cables attached, I went back to the engine and the jumper cables were smoking hot, scared the crap out of me. I quickly disconnected and stood back...needless to say the car is dead at this point. I'm ready to start to fix it, and would welcome any advice. What could short that could cause it to pull some serious current? Could the solenoid short out? Any trouble shooting tips would be greatly appreciated!

[bbodie52]

The hot jumper cables would seem to indicate that the current draw exceeds the capacity of the cables. (Some inexpensive cables have thin gauge cables that contain thin, small gauge wires. With inadequate current capacity the wire heats, and the heat continues to increase as you crank the engine for longer periods of time).

If you suspect that the jumper cables have inadequate capacity, could you try swapping the battery, or placing the old battery on a charger to ensure that it is fully charged?

With a good, fully charged battery installed with clean terminal connectors and battery posts, do the primary battery cables get hot when cranking the engine? If not it would seem that your jumper cables are inadequate, and the heat buildup is not caused by a starter failure. Your effort to start the car following a lengthy idle period without running the car, several attempts to start the engine, a troubleshooting step in priming the carburetors, etc. simply drained an already weak battery. A fresh battery connected by possibly inadequate jumper cables compounded the problem. There is also the possibility of an aging primary battery, shorted or weak cell, etc.

If you have a multimeter, what is the voltage provided by a "fully charged" primary battery? If there is a low voltaage provided by the battery, a weak spark from the coil could also result.

If the engine cranks OK with a good battery, have you checked the ignition system to see if it is providing a good spark at all spark plugs?

[potato124]

You were right! The battery was going bad, so the excessive current was due to a short in the battery. I swapped it out, and now it at least turns over! Now to figure out the carb issue...