UPDATE: The issue was the solenoid. With the tap of the hammer the solenoid reset itself and and my friend was back in business. Thanks again for all your help. I was helping a friend of mine replace his car battery in his 36 Flathead Ford and after the battery was in and the negative already attached I attempted to attach the positive terminal and it sparked and the darn engine turned over! Fortunately it wasn't in gear but what the heck is going on? This all happened without the key even being in the ignition. What would causing this to happen?
I'm guessing it has an external solenoid like most old Fords. Either the small terminal is receiving a voltage, or the disc inside it stuck between the large terminals causing a short circuit. Either would cause the starter to energize.
...and if a tap solves the issue, make sure to replace the offending part or permanently solve the issue in any other suitable way - you do NOT want the starter to be stuck on again once the battery is properly connected, not the same day, not a year later, so solve it permanently, don't be satisfied with getting rid of the symptom the actual problem has caused.
I have seen cables that were not installed properly and were making contact with the activating post on a solenoid. Trace the circuit from the starter switch to the solenoid even to go as far as unhook the start button to find the source of the problem.
Not the cause of your current issue, but years ago I was taught to disconnect the negative cable first and install it last.
Just to confirm, the car was working. He had a battery that he needed help replacing? IE “hey, come over I think I’m ready to start the old Ford”?
I had a friend years ago with a '67 four speed Mustang. When it rained, water got into the fender mounted solenoid, shorted it out, and made it lurch across his yard. Luckily, it never made it out into the street.
Thank you to all who responded. I'm going to try and answer all your questions. The car turned over properly with the key but after so many attempts to get it to fire the battery died. The battery itself was 5 years old so he decided to replace it with a new battery. We removed and replaced the battery and in the process we never touched anything in or around the engine bay (battery is located in the rear). The car is running a 12 volt system, electronic ignition with a large round battery switch in-between the battery and starter. We scratching head because the car ran prior to the battery dying. When I say dead, the battery was down to 4 volts. Could the solenoid have gotten stuck when the battery just couldnt turn the engine over anymore?
Stuck or seized from current draw are both options. Take your voltmeter set for continuity and check both of the large posts on it and see if it's open or closed. If it's closed, it's time for a new unit.
wfo guy has it . Stuck from current draw after "so many attempts" Things were likely a little hot and fused at the last attempt.
Once again, thanks to all of you who responded to my post. Going over to my buddies tomorrow, hopefully it's just the solenoid.
Yep, solenoid is probably fused. I had an old IH tractor that had been converted to 12 volts that would do that every once in a while. If the battery got too low cranking it over, it would stick, usually a tap with a BFH would unstick it, if not, it was new solenoid time. The solenoid on it sat outside the hood line, rain would drip off the hood onto it and get inside. With today’s subpar parts, I usually had to replace the solenoid every spring when I woke it up after sitting all winter.
So did you replace the solenoid as recommended, - or like me did you just carry on to fight the same problem another day………? ( ps, I actually sprayed some lubricant up my solenoid and it has been okay ever since ).