Voltage drop at the solinoid

[thriceaddict]

Hi Guys,
My neighbors kids have a four stroke ezgo (not sure what year it is but probably in the early 90’s) that they wanted help to get running again. After I towed it to my house, I tried pressing the gas peddal and there was nothing. Being an electrical problem, I started tracing the voltage through the system and found the first fuse (leading from the battery terminal on the solinoid to the reverse switch). I replaced that fuse and tried stepping on the peddal again. This time, I thought I heard a buzzing sound from the solinoid. So again I continued to trace the electrical lines. I traced all the way back to the smaller positive terminal on the solinoid (following the blue wire from the pedal switch) where I noticed a weird problem. If I unplug the blue wire that comes to the solinboid and test it, there is 12.5 V coming through. Once I plug the wire into the terminal, the voltage drops to 2.5 volts and I hear buzzing coming from somewhere around the solinoid. I then took the solinoid out and tested the continuity with and without 12v coming to it and everything checks okay. I also don’t hear the buzzing sound when I test it directly connected to the battery.
I tried connecting all the wires to the solinoid and jumping 12+ straight to the smaller positive terminal on the solinoid and the motor started for a few seconds but then the fuse popped again. I understood why the fuse went out due to the jump wire touching the blue wire .
I don’t understand what’s going on. Could it be the voltage regulator?
Any help is much appreciated…Thank You!

[barney1golf]

I would start by taking the battery to Autozone or somewhere and have them check it. Just because you have 12 volts on the battery doesn't mean it is necessarily any good. When they test it ,it will put a drain on it to see if it will hold the voltage. If that is the case, the low voltage going to the voltage regulator may be causing your humming noise. I would start there.

[walt-rate]

did you get your battery checked yet?? if not you can put a volt meter on the battery and try to start your cart, while starting it watch the meter, if it drops down to your 2.5 volts, the battery is your problem

[csason]

The fused line you spoke of that goes over to the reverse buzzer is just a loop to the buzzer to provide spark for it, the *other* side of the mini switch for it is the other side of the mini switch for the pedal.

You could take it out, if you catch my drift, at least in figuring out electrical problems.

yeah I guess once you have a hot battery, you can try crossing the solenoid with a screwdriver just to see if it turns over. Thats what I do, then, if you
check your hot on the coil side you are half way home. .(or pull a plg to see if you have spark then.)

[thriceaddict]

Sorry for the late reply and thanks for the advice so far. I live far from any auto shops but was finally able to go get my battery checked. They said it was bad so I tried a new battery...same problem.

To answer your question walt-rate, I did check the battery voltage while stepping on the gas and it does not drop. It does however drop at the solinoid post that the positive side of the battery is directly connected to. I have also tried jumping it, which again just makes the humming noise. If I unplug the blue cable that comes from the pedal switch going to the solinoid, then I read 12.7 volts coming through...but when I plug it back into the solinoid at the smaller positive terminal, the voltage drops to 2.5 volts. That tells me the system is fine till the solinoid. I can't really go any farther from there since the coil isn't getting power.

I also checked the line coming from the generator. As per my understanding, when I step on the pedal, the solinoid is supposed to let power to the generator (which works as the starting motor right?) When I test the power going through, there are only .5 volts and the continuity test just beeps randomly every 5 seconds or so. When I took the solinoid out and directly connected it to a battery, I got a nice constant continuity and no buzzing sound. Could my solinoid still be bad?

[walt-rate]

OK I printed out your last replay, and went out to my cart, I have a 2cycle cart but everything is the same up till your motor, I think it sounds like your solenoid is BAD, I've found many of them on e-bay for about $25.00-$27.00 W/shipping.. keep us in the loop with what happens next.. keep smiling things will work out..

[thriceaddict]

Just an update...I went to go pick up a new solenoid (and yes I just figured out I haven't been spelling solenoid correctly) and the sales rep started asking me the symptoms of the problem. We went through testing procedures for the solenoid and he said it might still be okay. The reason it is humming is because the low amount of voltage going to it. He then said that there are common cases where the motor is ground out. He explained that when a brush wears out in those generators, a mechanism inside that has current going to it can be touching the shell itself, thus grounding out the circuit. He told me to touch the 4 bolts on the generator with the positive and the shell with the negative. If I get continuity in any of the 4 bolts, it means I need the generator rebuilt. I will test this in the next few days and share what I learn.

[racin161]

LOL this is not a spelling bee. Keep us posted. If in fact the starter/gen needs brushes they are not hard to replace.You can replace the brushes only by just removing the rubber protectors to access the brushes or disassemble it and replace the whole brush plate assembly. With this procedure your able to clean everything. Oh spell check helps in the future.

[thriceaddict]

I performed 3 checks to see if the generator was ground out. I tried the continuity test first which came out positive. The wierd thing is though that I tried this test on a good generator and I was still getting a positive on the continuity. Am I perhaps doing this wrong?

Next, to make sure the solenoid wasn't the problem and that the generator was sucking up the voltage, I took out the generator lead on the solenoid and pressed the gas. The solenoid clicked and I got a beautiful continuous current to the other side.

Finally, I took the positive cable out of the solenoid, and hooked it up directly to the generator. I tried this with a working generator too. The bad generator didn't start at all which secured my diagnosis of the bad generator.

The only thing I am unclear about is why I got a continuous positive on the good generator when I put my lead on one of the 4 philips screws and a ground.

racin161...Do you have instructioons on how to install new brushes? Is there any other test to make 100% SURE that the generator is ground out? Will I be able to visually tell if the broken brush inside is what is grounding the system out?

[racin161]

Well to be honest when I did mine it was a piece of junk so I thought. I tore mine all the way down to find the brushes and brush plate a pile of rust.Being careful I removed the brush plate assembly and ordered a new replacement. I cleaned the communicator with light emery cloth as also the pole shoes. Everything looked good ie no broken wires and such replaced the brush assembly which I thought was going to be a pain but to find out if you leave the rubber protectors off while installing the rear cap and plate assembly and pry the spring out of the way until the brushes clear the communicator you can bolt it together push the springs over the brushes replace the protectors and you good to go. WOW ok that being said Two other things crossed my mind. Replaced my starter/gen and still nothing. OK what I found was f/r switch not making contact.Try cleaning it with carb or contact cleaner spraying it heavy and moving it to F/R and blowing compressed air into it. Maybe two or three times this should clean the contacts and may be the solenoid problem.Please make sure all the grounds are clean ie battery- battery to frame-frame to engine. REAL CLEAN