Battery help 6v with 8v battery won't start

Be sure you have a good ground, frame to engine too.

 

Battery cable size is real important when dealing with 6V. I used welding lead for my replacement on my truck. It takes bigger cable to run 6v copared to 12v. Everything has to be right or you will have problems that will escalate as time goes on. Check everthing, you should be able to get it running with the wireing harness you have , unless you have a direct short. Remember that neg. grnd. = the mius side of the coil for the ign. positve= + side of the coil for the ignition wire. A six volt starter will last a long time on 12 volts as you only use it a short time while starting.
Test-clean-check wire size-check conections and you should be OK.

 

Well here is an update.

I got out and picked up a load tester at Harbor Freight. Best 25 bucks I have spent so far.

Tested the 8v battery. At rest it was 8v. Pushed the switch down put the load on and it only came up just under 4v.

Time for a new battery.

Went and picked up a 6v battery for the truck. 550 cca.

Also found a ground wire almost broken off so there were some problems. I will be chasing more.

Put the battery in and fixed the wire and she fired right up. Now I have to figure out why the gauge in the dash says discharging when the truck is running. Maybe the gauge is bad or wires are switched backwards.

I also have to chase the dash parts down now. Gas gauge isn't working and the spedo is bad. pointer is broken off. Time to find someone that can repair the original back to new 6v specs.

Love these old trucks easy to work on.