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Lately the truck has been turning over very slowly and has let me down by not starting at all.
I put my cheapo multi meter on the battery posts and it shows at a little better than 6 volts when static, when revving the engine I get no change in voltage but the dash gauge shows it is charging. The voltage regulator was replaced in May and the generator was rebuilt about 2 years ago. System is still 6 volt positive ground. Are there any tests I can do that may narrow down the problem?
Ed
near Philadelphia
Sometimes the brushes just get hung up in the holders, the springs don't apply enough pressure, in any case they aren't making good contact with the commutator.
If you are very careful, with the wheels chocked, parking brake on, in neutral at a fast idle take a wooden wedge or similar tool and jam on the back of the brushes through the access slots, so they make solid contact. Spray some non-residue brake cleaner or electrical motor cleaner in there too. This may or may not get you going again, but it's simple enough to try. Or the brushes may be just be worn out. They should be good for a long while though, if it's been recently rebuilt.
I had some similar problems that were fixed by taking the generator apart and cleaning Up the commutator, brushes, etc.
it really only took about a hour total to get the generator out, cleaned, and back in. I would start there.
i don’t know the details but I think if you ground the field it will charge up(increase the volts) very fast which implies it’s charging. Check the shop manual for the specifics.
Analog voltmeter is necessary too, if you start to get into it. A modern digital voltmeter will work to measure charging at the battery but anything beyond that, it will get confused by the choppy waveform or pulsed output from the regulator. Yeah the manual is your friend here.
One easy thing to check is use a pair of jumper cables and connect one end to the (ground) terminal on the battery and the other to the generator case itself. See if charging resumes. If it does, then there is a ground problem.
"Full Fielding" the generator tests whether the generator itself is OK. It's pretty simple to determine if the generator or regulator is at fault. Be sure to follow the correct tests or troubleshooting procedures for a Ford or type "B" generator. Tests for other makes will roast something. That's where reading it in black and white is best.
I have been "around the block" on 6V charging systems! The highlights are documented in my " Holley 1904 carburetor" thread. The thread is very long, and you will want to skip to the last few pages to read about my struggles with my charging system. Bottom line, my problems were the result of a weak circuit breaker.