85 G2 not charging even after checked & replaced everything

redmuns

I have ’85 Yamaha G2 gas golf cart that will only run for 20-30 minutes on a good battery, then it the volts are gone. I have replaced the battery, starter/generator, and voltage regulator and still have the same problem. I have 12.5 volts at the battery with a fresh charge, start the cart and volts drop 11.2 when I rev the engine no change. I have read every post on here about charging and used them to trouble shoot this issue and everything is connected correctly and I have continuity. What else should/could I do or check or anything? I have done a rebuild on this and mechanically, this is the only thing that is not working. I have already spent way too much if this is a junker!

BGW

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bigstik40

You need to do a couple quick checks as follows:
1. Confirm that the voltage regulator D+ terminal (R/W wire) has 12 volts on it with respect to bat. (-).
2. If you have +12V. at D+, remove the green wire from the Df terminal of the voltage regulator. Attach your voltmeter to the (+) & (-) battery terminals, then run the cart either in neutral or with the rear wheels jacked up. With the cart running, momentarily jumper the green wire (the one you removed) to the bat minus (-) and note the voltmeter reading (it should be in the neighborhood of 16 volts or more if the st./gen. is ok. (Note-only hold the green wire to bat. (-) long enough to get a voltage reading !) This is applying full field current to the charge windings and should be done only momentarily for testing!

Let us know what you find and we can go from there - RAY

Mike Mac

Red, your in good hands now!!

G1-G9

i had to take my wiring harness all apart and when i did i found the wire that was broke and a lot more that were rubbed bare.

G1-G9

P.S. we like pictures

smallblock450sl

I agree, about all it can be. Ohms check at red and green wire's comeing out of feild of starter/generator-5 ohms. Check for continuity (on wireharness side to voltage regulator) of the red and green wires and continuity of black wire to battery. Good luck

redmuns

Thanks Guys, I am going to check it out this weekend. I will post with results.

redmuns

OK, I just got done checking that the voltage regulator D+ terminal (R/W wire) has 12 volts on it with respect to bat. (-). I just need to make sure I did this correctly. Without the cart running and fully charged battery in the cart, I connected the (-) from the tester to the (-) on the battery and the (+) from the tester to the D+ terminal (R/W wire). I have 0 voltage registering on the tester. Did I do this correctly or should I have had the cart running?

bigstik40

Cart should be running when measurement is taken. The key switch and the accelerator switch close to energize this circuit. Sorry I wasn't clear on this . You can jack up the rear wheels or run in neutral (if you have this feature) to make measurements and tests a little easier. RAY

redmuns

So I wanted to check what the battery was before I started any testing, it was 11.20v. Then I checked the voltage regulator D+ terminal (R/W wire) with respect to bat. (-) with the cart running, and I get 9.20v. So I took the green wire off the DF terminal, and put a jumper wire to it, started the cart connected the tester to the battery terminals and connected the green wire to the (-) post and the voltage stayed at 11.20. When I touched the green wire to the (-) battery post there was a small spark. I can see that there isn't +12v. Now, keep in mind that this is a new starter/generator and voltage regulator; however I had the same exact problems with the old starter/generator and old voltage regulator. What's next?