91 Marathon rehab questions

[joej85a]

Hey guys, i just picked up a 91 marathon from my neighbor and i am evaluating whether to proceed with the rehab or not. From reading around on here, it appears to be a 91 series model. When i picked it up the previous owner had pulled two of the batteries but said it ran. Just to test, i topped off all of the batteries with some fresh battery acid and put a charger on her for about 6 hours. Quick check of the wires and everything seems in place. Switch on, peddle down, and nothing. Not that i was that surprised, so i plan on going through the wiring etc tomorrow with my dad thanks to the diagnostic section and the wiring diagrams posted.

My main question is this, even if the batteries are OLD, i am getting a 6v+ reading on them, is that enough to see if it is functional and do the diagnostics? I am trying to avoid putting $500 worth of batteries in it only to find that the motor an controller are shot and so is everything else.

I know the solenoid is not clicking, so i will start there. Anything else i should know or do right off?

Thanks everyone! Joe

[GrannyGoneWild]

Go read the stickies in electric ezgo forum or do a search on batteries. I have been told that each battery should read about 6.5v and the main pack when fully charged should be around 37.6? I am new and a real novice but have the same issues. There are some really educated people on this site that can help just be specific in your questions.

[JohnnieB]

Here is a State of Charge chart for batteries. As you see, 6.5V is a bit high for a 6V battery and 37.6 is only about 85% charged for a 36V battery pack.
Fully charged, a 6V battery will read about 6.37V and a 36V battery pack will read about 38.22V
Those reading are taken about 12 hours after the batteries have been taken off charge.

You mentioned the word "controller", so here is a schematic for a Marathon controller cart with the solenoid activation circuit traced.

BTW - With two batteries pulled from a 36V battery pack, you have a 24V battery pack, which might not energize a 36V solenoid.

Also, lift rear wheels off ground (put on jackstands) so the half ton cart doesn't take off unexpectedly and run over somebody or into something.

[joej85a]

Thanks for the info guys. I have installed all of the batteries back into the cart and will check the reading when i get home.

Quick question, were is the best place to get a reading on the total voltage? I was checking at the plug for the charger.

Ill keep you all posted

[JohnnieB]

Originally Posted by joej85a

..............Quick question, were is the best place to get a reading on the total voltage? I was checking at the plug for the charger................

Cart's charger receptacle should read total battery pack voltage, if everything is connected right.

Here is a drawing showing the correct orientation of the batteries, how they are interconnected and where the main leads go to as well as where to attach the Negative test lead of your DVM for most voltage measurements while troubleshooting.

[joej85a]

ok guys I am in the garage with the cart. It has come off a charge for about 3 hours now and i am getting 36.8 at the charger, so it is only showing that it has a 60% charge. I am still getting no clicking or anything from the solenoid, so I have taken off the wires and am cleaning all the connections and checking for broken wires. The previous owner put a toggle switch in place of the ignition, so i am checking to make sure the switch is actually activating the system.

[joej85a]

ok update. I cleaned all the wires on the solenoid and noticed a little wire that goes between the big studs of the solenoid (another resistor?) had a broken wire. I also noticed that someone had mucked with the gas peddle linkage at the solenoid. Apparently there is a little switch that is pressed when the accelerator is at rest. well the little arm doesnt reach that switch i could take my finger and press it up and it would click, but the linkage is not making contact.

Still no dice on getting any sign of life from it yet.

[joej85a]

FIREWORKS! Needless to say i found one issue. The switched power wire coming from the ignition was going to the MS4 double pole switch on one of the speaker outputs. I moved it to the correct MS2 switch, flipped the switch on and BANG! it blew the resistor (or diode?) between the little poles on the solenoid. I am sure that is not a good sign, but i am wondering, that circuit passes through the MS3 switch, which is the one that the accelerator linkage is not closing, so when I flipped the switch did it think the accelerator was down? So at this point, the diode and the resistor are off the solenoid. Any thoughts???

[GrannyGoneWild]

I told ya I was a newbie I see JohnnieB corrected my bad info. Johnnieb is the best! He will teach ya how to be dangerous!

[joej85a]

UPdate: Man this thing was wired all kinds of wrong. I got my ms3 switch working, had to adjust the throttle linkage to get it to close, but the DMM is confirming the switch was working. I was then tracing all of the rest of the wires and the PO had reversed to of the large cables coming from the F/R switch. He had B and C reversed. I fixed that, and got everything reconnected, flipped the ignition switch and no fireworks this time! I quickly hit the accelerator and the switch clicked and then the Solenoid clicked. Good news is i am getting more action than i had before. But now i am at clicking solenoid with no GO.

Is it possible my batteries lack the juice to make the wheels turn? Or where should i go from here? Potentiometer? Control Module?

The guy said they had put a new motor in it, and that seems to be the case. It is a GE series wound motor, 3.5 hp, 3000 rpm 91 amp.

Next?