1989 EZGO Marathon Electric wont go.

[JohnnieB]

Originally Posted by john_fulton

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1. If this does not work how can I test to see if my motor is good? The motor did work when I brought it home.
2. Where can I order a new controller and throttle for it?
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1. If the motor worked when you brought it home, it probably still works. The motor is the most robust part of the electrical system, but they do fail.
Attached is a way to test a series motor.


2. A golf cart is designed to carry two golfers and their clubs over groomed cart trails for about five miles in 20 short trips (18 holes plus trip to and from cart barn) with a pause of several minutes between trips. If you plan to do more than that, the cart needs to be upgraded.

In fact, a 25 year old cart most likely needs much of the drive system's electrical components replaced just for reliable golf course use, so it is logical to replace the OEM stuff with marginal capabilities with more robust components. IE: The original 6Ga high current cables (all 13 of them) should be replaced with 4Ga or heavier cables.

The site linked to has a fairly decent overview of what should be taken into consideration when upgrading a cart for uses more demanding than golf. http://www.cartsunlimited.net/Custom_Options.html

Also, there are several other site sponsors that have a wide varity of stock and upgrade parts: http://www.buggiesgonewild.com/site-sponsors.php

[JohnnieB]

Originally Posted by john_fulton

Ok, the pot makes no difference. I still cant get the tires to spin so it is down to the controller or the motor. I assume since I get voltage out of the solenoid when the micro switch is released that the forward and reverse switch are working.

There are two (or three) microswitches and a high current switch on the F/R switch assembly. The fact the solenoid energizes, verifies one of the microswitches works and that there is conductivity through part of the DPDT high current switch.

Connect your DVM between the controller's B- and M- terminals.
Push pedal just far enough for the solenoid to click and you should read FULL battery pack voltage.

If you don't there is an open, or high resistance, in the high current loop.

If you get FULL battery pack voltage, slowly push pedal to floor and the voltage should smoothly decrease to near zero volts.

If not, the controller or the throttle input to the controller is bad.

[john_fulton]

I am going to run a bunch of tests and will get back to you all this evening.
Thanks again for the help.

[john_fulton]

Update time. I tried spinning the back tires and the drivers side tire spins with a little tension but the passanger side tire is very hard to turn. The next thing I did was to make sure the solenoid was working agian. I measured 38.1 volts on the power side and zero on the other. When I activated the solenoid I read 16.4 volts on the other side. I then took the cable off that goes to the controller and then I read 38 volts. I did notice I do not have a resistor or a diode on the solenoid.
I then put the negative lead on B- and the positive on M- on the controller. When the solenoid kicks in I get 16.4 volts and it does not decrease as I press the peddle down. I do not feel any heat anywhere or smoke.

[john_fulton]

My next step is to remount the old potentiometer and adjust it so it ranges from 0ohms to 5000ohms. and then repeat the solenoid test and the B- to M- test.

[john_fulton]

OK so I soldered the old pot back on and ajusted it so it ranges from 0ohms to 4.86kohms at full throttle. With the controller cable attached to the solenoid I still get 16volts when the solenoid is activated. Same thing with the B- to M-. There must be a short in the controller. Can you rebuild these or do you have to send them in?

[radioman]

Whoooa wait a minute...If I am reading your post#24 right you measured 38.1 volts on one side of the solenoid contacts and 16.4 on the other big terminal when energized? If so it appears you have a faulty solenoid contacts and it is faulty because the resistor is missing. It is possible your controller is ok. Double check the voltage on both sides of the solenoid big terminal lugs. Don't bypass the contacts yet. You will get a big spark if you do. You need to obtain a resistor first and possibly a new solenoid. The cart is not going to move on 16.4 volts from the solenoid.

[john_fulton]

But when I pull the cable of the other big terminal then it reads 38volts. Is that still the solenoid doing that or the controller pulling down the voltage? So are you saying to replace the solenoid and put a resistor and diode on it? Thanks for the response.

[radioman]

Originally Posted by john_fulton

But when I pull the cable of the other big terminal then it reads 38volts. Is that still the solenoid doing that or the controller pulling down the voltage? So are you saying to replace the solenoid and put a resistor and diode on it? Thanks for the response.

Unless someone else has another opinion yes. The solenoid contacts are shot from the surge the controller drawns charging the controller because the resistor is missing. Double check the voltage. The controller is pulling the voltage down because the contacts are shot and has resistive connection. I cant believe this is so simple. If you bypass the solenoid contacts with a jumper you will get a big spark. If the controller was shorted you wouldn't get any voltage out of the solenoid.

[john_fulton]

Just ordered a heavy duty solenoid, resistor and diode. Should get them thursday hopefully. Will let you know how it goes. After that I guess I am stuck getting a controller if this does not work.