1991 ezgo marathon speed issue

[spacityhog]

I have a 91 ezgo marathon giving me trouble. I bought it from a neighbor and the cart would die when the accelerator was pushed halfway down. It would go when I let up on the pedal. I changed out the potbox and that fixed that issue. Now the cart runs very slow. It ran much faster with before the potbox was changed. I'm thinking it might be the controller. How would I test that? Any other ideas? Thanks in advance...

[spacityhog]

also...batteries are 6 months old.

[JohnnieB]

If the same controller ran the cart faster with the old pot-box than it runs it with the new pot-box, I'd check the new pot-box for proper adjustment.

Pull the black and white wire off the controller and measure between the two wires (not the terminals on the controller) with an Ohmmeter. Should be about 0Ω with pedal up and about 5,000Ω with pedal down. (In Reverse, it may only go to 2,500Ω if half speed reverse switch is connected.)

To check if controller is wide open when pedal is on floor, measure the battery pack voltage when running flat out on level ground and then measure the voltage between the M- and B+ terminals on controller while doing same. They should be exactly the same if the controller is at 100% duty cycle.

FWIW: The controller shuts off if it sees more the 7,000Ω between the black and white wires, so the old pot-box might have simply been out of adjustment.

[scottyb]

Another FYI is this - The cart had a 1/2 speed reverse option. The cart will be slow if you somehow have activated the 1/2 speed pot signal all the time.
The OEM pot had 2 sets of 2 wire leads. One set sent ohm signal to the control. Second set reduced that signal 50% when connected together.

Measure the ohm output from the wires to the control... what do you get?

[Ajaysummer]

Originally Posted by JohnnieB

If the same controller ran the cart faster with the old pot-box than it runs it with the new pot-box, I'd check the new pot-box for proper adjustment.

Pull the black and white wire off the controller and measure between the two wires (not the terminals on the controller) with an Ohmmeter. Should be about 0Ω with pedal up and about 5,000Ω with pedal down. (In Reverse, it may only go to 2,500Ω if half speed reverse switch is connected.)

To check if controller is wide open when pedal is on floor, measure the battery pack voltage when running flat out on level ground and then measure the voltage between the M- and B+ terminals on controller while doing same. They should be exactly the same if the controller is at 100% duty cycle.

FWIW: The controller shuts off if it sees more the 7,000Ω between the black and white wires, so the old pot-box might have simply been out of adjustment.

I am wondering if the pot box is to blame for my current issues as well (1991 EZGO marathon). The cart just decides if it wants to go or not randomly. Solenoid clicks every time and voltage across the terminals is checking out even when the cart isn't going. All my connections so far test out just fine (tested up to the pot box and controller, but having trouble really troubleshooting the controller like I was reading in a previous thread). If the pot box is the issue and is shutting the controller off, how do I "adjust it" like you mentioned? Or would I have to replace it?

[Golfcartmangreen]

I’m having a similar problem , I’ve changed the solenoid , the pot box , the F&R board , cart still runs slow at first then quits, out of options , any suggestions?