OldIHC

I have two questions. First, I didn’t realize that the truck was supposed to have the positive wires it to ground when I replaced the battery with a new red top optima. Ran it twice like this and the am meter is reading like 25 amps when the truck now is running (I did swap it around). Did I break anything or is the battery just charging ( I have only run it once the correct way since). Second question. My truck is having a hard time starting after it sits for a brief while. It maybe a tad bit tougher to get it to start when it is dead cold, but two times now I have shut it off while running brief errands and it is a bear to start. The most recent time i had to let it sit for over an hour then after several long attempts I got it running. Any thoughts what I should look at first? Still the orginal engine, zenith carb and has the 6v electrics. Thanks for any help!

Generator systems are very robust, so likely you did no harm. You would have killed a alternator!

Make sure you have adequate grounds in all the right places, the braided ground straps are pretty! Pretty useless. Go directly to the starter for the ground, Did I get that correct CB?

I think I read somewhere that one of the differences between pos. and neg .ground is the direction the spark travels at the electrode on the spark plug and there are advantages to the pos. ground direction .

Last time I had an engine that started easier when it was cold than when it was hot the condenser was at fault.
b4autodark

I believe Manic is correct with the spark jumping. There was some discussion I've read before, if the coil was connected with the opposite polarity.
The reason the truck started was because the starter still ran in the correct direction. Either the armature or fields need to have their polarity changed to run in the opposite direction. But with the battery connections switched, both the armature and fields were switched, so same direction.
Did you try a shot of gas or starting fluid fluid down the carb when hot? Possibly the insulating spacer, bakelite or whatever material, is not there. Causing the carb to get hot. If adding a fuel down the carb allows it to start, then it's a fuel delivery issue. If not, then an electrical issue. If cranking and not starting, you can pull a spark plug or coil wire off and check for spark.

I changed my 1953 R120 to 12 volts. The starter worked and turned the way it did originally. I changed the coil to 12 volts and made sure the +/- were connected correctly. The (-) went to the points.
On the matter of the fuel and hard starting, I added an inline check valve because the fuel was returning to the tank past the mechanical fuel pump.
Here is the interesting thing. I rewired the OEM gauges for 12 volts with negative ground and the gauges continued to work for the next two years.
http://firetrucksandequipment.tpub.com/ ... -1_545.htm