2003 Ezgo txt high voltage while running
 

I have a 2003 ezgo txt with a gas robyns engine, Was having issues with power being intermittent, while I had golf cart down to wire some head lamps, I pulled the starter generator and cleaned the contacts and checked the brushes, at the time they were getting close to the full wear mark, it worked a couple weeks and then started being intermittent again, you could rotatate the starter generator and crank by hand to change the contact positioning and sometimes it would work… I went ahead and decided to just replace the starter generator instead of replacing the brushes (the internal bearings of the starter/generator had some wobble so I just replaced it) - installed with no issues exactly per the diagram as well as same as previous part, cart ran good for about 2-3 days and son was driving and the starter generator pretty much grenaded, which also made the starter/ignition solenoid stop popping, company warranty the starter generator and I replaced the solenoid, and the fuse (7.5) that was blown from my spark plug coil- cart is cranking, starting, and firing fully, but I was skeptical after the starter generator blowing up, so I wanted to check some more stuff before hitting the road -

I am getting good voltage (12.8 volts) at the battery, but when the engine is running/firing - the voltage jumps up to almost 17-18 volts at full RPMs, didn’t really trouble shoot any other than checked the green DF wire to make sure the terminal looked secure and not shorted, so I replaced the voltage regulator, but now the son of a gun jumps up to almost 18-19 volts at full rpms, the green wire that comes off the starter generator and goes back to the voltage regulator (8mm terminal) - when I disconnect it and ran a jumper back from that terminal to the voltage regulator it’s still doing the same thing so that green wire isn’t shorted to ground anywhere… so I disconnected the jumper that I put on, plus removed the green wire from the bundle, so there is literally nothing connected to the starter generator running back to the voltage regulator which should be fully removing the voltage regulator from the circuit, there is not much difference when I have the voltage regulator hooked up or not 🤦*♂️I got the voltage regulator from the local ezgo dealer— is there a chance that the voltage regulator could be bad or a way to bench check it, I am guessing that a voltage at the battery on a cart shouldn’t be that high, guessing like a car just a couple volts over the resting volts so I figured it should be somewhere around 14.5-16 at running or high rpms would be normal - any input or help would be greatly appreciated- definitely don’t want to spend more money on a starter generator or voltage regulator

Re: 2003 Ezgo txt high voltage while running
 

Troubleshot as much as I could, but everything was leading to a faulty voltage regulator; replaced it and volts are back to what they were previously- I’m at a lose and not sure what is causing the overcharging

volts at battery terminal

Orignal
Resting- 12.6
Running (3/4 rpms)- 17 to 18 volts

1st new part
Resting- 12.6
Running (3/4 rpms)- 18-19 volts

2nd new part
Resting- 12.6
Running (3/4 rpms) 17-18 volts

Re: 2003 Ezgo txt high voltage while running
 

Still no solution found- still recharging at 17-18 volts….
Does anyone know if a bad battery could cause this?
Or any potential grounding points that I should check?
I would think that ground from the voltage regulator is
good since it shares the ground point with the solenoid
And it’s working- Could the solenoid potentially be creating
A short to ground issue after it allows the cart to send power
To the starter? Any help would be appreciated

Re: 2003 Ezgo txt high voltage while running
 

***UPDATE***
Issue has been resolved, just as I was suspecting after troubleshooting the
Starter generator was internally shorting the field coil wire to the case which
Which was causing both F terminals and DF terminal to constantly show
Continuity to the case- looked like the manufacturer knew about it and tried to
Fix it with some insulator paper but it had shifted- I moved the wire from touching the housing and wrapped with insulator and sure enough all three terminals were good- re assembled and installed on cart and sure enough the voltage is 12.7 resting and 14.6 charging at high rpm’s - highly recommend bench testing any admiral MOT-2003 starter generators before you leave the Supplier - most won’t warranty, they are very expensive, and I had two consecutive parts that were both crap with separate issues -

Re: 2003 Ezgo txt high voltage while running
 

At a minimum I will always take a multimeter with me when buying a starter generator and check continuity - if your get an Admiral MOT-2003 here’s the tests that I would check before leaving the supplier!

1st test -
(-)black lead grounded to housing (checked both end caps and middle section with paint removed)
(+) Red lead tested on each A1, A2, DF, F1 and F2 - my thinking was all terminals should have no continuity and read OL on meter
Results
A1: OL
A2: OL
DF: OL
F1: OL
F2: OL

If the F1 or F2 reading is incorrect, it indicates a possible grounded F1 or F2 terminal or a grounded field coil.
If the DF reading is incorrect, it indicates a possible grounded DF terminal or a grounded field coil.


Test 2
(-) black lead- A2 terminal
(+) red lead - A1 terminal
Results = 0.0 (cont)

Test 3
(-) black lead - F2 terminal
(+) red lead - F1 terminal
Results = .1 (cont)

Test 4
(-) black lead - F1 terminal
(+) red lead - DF terminal
Results = 5.5 ohms

Don’t accept the part unless your readings are good- if they have a power supply you can also have them show you it starts with power, you won’t be able to check the charging circuit without the voltage regulator but if your terminal readings are good you should be good to go when you install it back onto the cart

Re: 2003 Ezgo txt high voltage while running
 

You did a lot of research with good detailed information. I was going to link this thread to one of the sticky pages, but couldn't find one unlocked that dealt with similar subject matter.

If this info is going to get saved, it will have to be done by a moderator.

Re: 2003 Ezgo txt high voltage while running
 

I had exactly the same (intermittent) over charging issue after installing a new voltage regulator and starter/generator on my 2010 RXV gas cart. I beat my self up trying to figure it out over a couple days in near 100 degree heat.

Installed a new voltage regulator and starter/generator. Running at full throttle, I got up to 18 volts at battery with the green wire connected. After another new voltage regulator (thinking with my luck I got a dud), I had the same problem. I disconnected the green wire at the DF terminal thinking the wire might be grounded. Same condition. I removed the new starter and reinstalled the original starter/generator and the voltage was then regulated at 14.8 volts max.

My guess is (based on your situation) that DF terminal being grounded to the frame internally, caused generator to backfeed through the power cable at the solenoid, and feed unregulated voltage directly to the battery. That condition would bypasses the voltage regulator circuit. I may very well run into the issue again with the old starter as it was an intermittent problem to begin with.

Just a side note: I was careful when attaching the green wire to the DF terminal post as to not twist it to cause internal shorting.

I bought the new starter/generator on Amazon with free returns and free return shipping and glad I did. If I had had no defective issue, I would not need to return it (which is hard to accomplish with any electrical items at most all venders). It's irontic that the vendor sells the item stating no returns on electrical parts, and you install it and even if it is defective, it is considered used and usually unreturnable. That was the reason I used Amazon Prime as it allows free returns and free return shipping for any reason even though the selling vender states otherwise. (I havent got my return yet but hope they are true to their word). I will post if I have any problem with that.

Hope you can figure out what I'm trying to explain here. My first time posting. Old Stan