2003 48V Carryall lurches in fwd/reverse

[odiethe1st]

Need some help on my 03 CC Carryall 48V, have been using the cart about 2 years around the house and with increasing frequency...the cart lurches abruptly in forward or reverse. Seems like the lower gear (or two) is skipped...reminds me of doing a "transmission drop" in a car.

Details: Stock Curtis 1204-410 controller and motor, cart is lifted with oversized tires. Batteries a few years old, holds a great charge.

History: Noticed the bushings for accelerator shaft were worn out (thought maybe the delayed response started there) and replaced. Issue subsided for a while and seemed to gain top end speed (12 mph to 17 mph) Once issue was constant, replaced the MCOR with an internet buy...issue was the same. Cursing cheap parts off the internet, then tried another from an 07 Carryall 48V cart I just bought. Same thing.

Summary: There have been 3 MCORs installed and the issue is identical, I've read (on this resourceful site) about components to replace for each speed range on older CC models...does this model cart have them? If so, how to check? What's next to troubleshoot?

Many thanks!

[odiethe1st]

To update: After sitting indoors for several days, the problem seems to have subsided. Low speed control is back, but now a worse problem...even with a fresh charge, the cart will only go a short distance (a few hundred feet around yard) before it acts like batteries are dead. Pack voltage was 51.8 volts after recharge & before the last attempt...still showed 50.4 volts when it died in the yard.
The batteries have plenty of water. Except for three battery connections that had some corrosion, the cables & ends looked fine.

Given the two problems, I'm leaning toward trying a rebuilt controller. Would love to hear some other thoughts before I spend that $300...whatcha got?

[odiethe1st]

For closure and maybe help out someone having the same issues. Installed a rebuilt motor controller and issues are solved.