Cart jumping when throttle pedal pushed

[Fleck]

It's been a long time since I've been on here because me cart has worked flawlessly until now. I leave in a cold winter climate during the winter so my cart sleeps all winter. I keep the batteries charged during the winter. I went out to get it ready for the summer and having lots of issues with it.

Let me start with specifics of cart. It's a EZGO Marathon resistor to controller modification. 48V, Tyco soleniod, Logisystems 700V controller, 7hp GE motor. When it noticed the problem I checked pack voltage (52.1), Checked and cleaned all connectors one by one, Swapped soleniod with one that was confirmed to work and then back to tyco soleniod.

Here are the issues. First I tried to back it out of the shop. It made a wistle sound when the throttle was pushed (tried to move but wouldn't). Gut it up on jack stands and tried again. Wheels would spin but slowly and still wistled. after messing with it for an few hours the wistle went away and it seemed like it was working great. lowered it onto the ground and pressed the throttle. Cart jumped violantly and almost threw me off. Put it back up on stands and pressed the throttle it seemed fine. Called it an night and started over again today. Press the throttle today and it seems fine for a few seconds and wheels slow to a stop. Let off throttle and hit again and get nothing but but soleniod click. Nothing is hot to the touch. I'm stumped. Tryed looking for test procedures for motor and controller and can't find anything. Also tried calling Logisystems to talk to Jim but the number I have goes right to a fax machine sound. Don't even know if they are still in bussiness.

Any imput would be greatly appreciated since I planned on taking the cart camping wednesday morning. Really wierd that a gremblin got into it over the winter.

[Fleck]

I have a stock working Curtis controller but it is only 36V that i'm thinking about using just for testing purposes but really dont wanna risk letting the smoke out of a goon controller.