1992 EZGO Marathon

[outdoorsman.rc1988]

Hey guys, new the forum. I recently acquired a 1992 EZGO Marathon cart from a friend of mine. The car has a controller and not the speed resistors. He replaced the 3 batteries in 2013 and the other 3 are OLD, the labels were worn off. The car has been drove very little in 2 years. On initial testing the battery pack had 35v. With the charger plugged in it was reading 40-41v. After charging, I let the battery pack settle for a few hours and it was reading 37-38 volts. Went for a test ride and it had very little torque, I almost had to give it a push start to get it going. Once it got moving, it was actually pretty fast. I let it sit for about 12 hours and the pack was around 36v so I replaced the 6 batteries. After installing the new batteries and the jumper cables it was reading 39-40v. Went for a test ride and the same thing NO TORQUE!!! After a very slow take off, it did get up to speed. I also replaced the solenoid and tested the POT box, no pedal zero ohms, at full pedal 5500 ohms. I cleaned the contacts on the FNR switch, cleaned terminals on the controller and cleaned the motor terminals. Does anyone have any advise? I'm thinking the controller may be bad. Any help is appreciated. Thanks!!!

[Sideways]

Sounds more like a loose connection somewhere, check and double check everything.
I would also make sure the brakes are not sticking.
Anything above that is above my paygrade. but others should chime in

[jayp1017]

Look at your forward reverse switch again...are the contacts level with the board?

If those are ok you'll want to look at the brushes on the motor...take the back cover off there will be graphite brushes that are pushed by a spring mechanism...original brushes are about an inch long and should be sticking out the back of the holder they are in...if they are worn you can buy new or you can just cut a peice of wood or whatever the same size for a spacer and glue to the top of the graphite where the spring makes contact...this will give ya a little more life without spending $100. There are 4 graphite brushes 2 for forward 2 for reverse...the more worn ones are forward as that's what you use the most. Now you can also just switch the brushes take the forward ones and use for reverse vise versa. You'll also want to check the wires on the brushes make sure they are not burned or frayed.

I'd bet it's the brushes tho...post a pic of your findings!

[jayp1017]

https://www.wantitall.co.za/automoti...go__b0155kmsrc

The whole assembly should look something like this

[outdoorsman.rc1988]

Jayp1017, thanks for the link. I am going to check on the motor brushes tonight. I'm new to the golf cart game so all advise is very helpful.

[outdoorsman.rc1988]

Originally Posted by Sideways

Sounds more like a loose connection somewhere, check and double check everything.
I would also make sure the brakes are not sticking.
Anything above that is above my paygrade. but others should chime in

Good advise! I actually have the brakes adjusted all the way in so there is no dragging. I will continue to check for loose connections. Thanks

[outdoorsman.rc1988]

Ok guys, sorry for the long post, I tore down the fnr switch and found that the terminals were not making good contact. In forward one contact was 6ohms, and the other was open. In reverse one contact was 11ohms and the other was open. I put a small shim behind the post that I determined was the "short" post. Put it back together and now both contacts in forward and reverse are reading 5-6ohms. This still seems high to me but maybe that's normal. Next I checked the pot again. No pedal reading was 0ohms, full pedal was actually 6000ohms, how can I get this down to 5000? Do I adjust the linkage? Next I checked the voltage across B- & M-. With pedal mashed just enough for the solenoid to close it had 39v, with pedal to the floor it has 33v. I was told this should be close to 0v. Next I pulled the motor and looked at the brushes. They are worn down as to be expected with a 26 year old motor, but they are not worn down enough to be considered BAD! Any thoughts from the BGW team. I don't know what to do at this point.

[cgtech]

Originally Posted by jayp1017

Look at your forward reverse switch again...are the contacts level with the board?

If those are ok you'll want to look at the brushes on the motor...take the back cover off there will be graphite brushes that are pushed by a spring mechanism...original brushes are about an inch long and should be sticking out the back of the holder they are in...if they are worn you can buy new or you can just cut a peice of wood or whatever the same size for a spacer and glue to the top of the graphite where the spring makes contact...this will give ya a little more life without spending $100. There are 4 graphite brushes 2 for forward 2 for reverse...the more worn ones are forward as that's what you use the most. Now you can also just switch the brushes take the forward ones and use for reverse vise versa. You'll also want to check the wires on the brushes make sure they are not burned or frayed.

I'd bet it's the brushes tho...post a pic of your findings!

THIS IS RIDICULOUS!

the brushes get really, really hot in normal operation = flammable stuff and glue Bad!
All 4 brushes are used during operation in both directions.

I would get a measurement of voltage at controller terminals B+ and M- during operation. If it never reads full pack voltage at full throttle, controller likely shot. I don't have much faith in that shimmed F&R either.

[jayp1017]

http://www.golfcarcatalog.com/golf-c...rator-brushes/

[jayp1017]

The link above should help. This is for a starter motor but applies to most all electric motors. I'm telling you those brushes are worn...they should be much longer...I know I said they should be an inch but the actual measurement is as follows 1-7/16"L x 5/8"W x 1/2"D.*So they should be about 2 inches long. Site sponsors may have their opinions and want ur $$$ but I'm here to help ya not sell ya stuff. The best thing to do would be to get new brushes or you can try what I suggested...its up to you what you do with the info. I think the shim idea is great and I've done it myself never had a problem. It is true that those brushes get hot but not hot enough that your going to cause a fire...at least it has never happened to me. If your that worried you could wrap the wood in aluminum foil or better yet go to an electric motor repair shop and ask if they have any peices of graphite that you could have and put those in front of the spring (the link tells you about the "pigtale" wearing out to the bottom of the brush guard which can cause arching so it'd be best to have the scrap graphite actually contacting the armature but how you "glue" and make that connection without compromising it conductivity I'm not sure how that'd work) ...Ive always done the spacer on the spring and had good results for a couple years but eventually replaced them. I would test with the wood to see if that's ur issue before you get all creative or spend money. Take that whole assembly out and feel the wires to make sure they are intact...they sometimes become brittle and break...if that happens crimp them back togeather. I'm sure I'll get a lot of flack for my recommendations but I just smile and move on. Keep us updated with ur repairs!

By the way...if you can ever get ur hands on a gas cart that's the way to go in my book...electric carts have to many things that can be wrong and a lot of diagnosing to figure out what's wrong. Gas spark compression...easy as that!