Clicks all the time

[Papas 73Dart]

I am looking at a club car DS 2001(AA0131) and when you take off the solenoid clicks constantly until it gets up to 7-8mph and the cart jerks. The previous owner thought it was the solenoid so he installed a new one. Too bad didn't make a difference . He sold the cart to my neighbor and he asked me to check the problem.
I cleaned all the battery connections and made sure the pack voltage was right up (49.7v) and checked all connections at the solenoid and motor all good
The cart has a mcor on the frame and it has a cracked case also someone drilled a hole in the cover I suspect to spray in contact cleaner .
I have a used mcor from a1999 DS cart that I tried. I jacked up the rear end and just connected the wires to the used mcor and ran I'd with a screwdriver to test it. The cart still had the odd click from the solenoid but nothing like the original .
And the motor ran fine, is there anything else I should look at first or does it sound like I should order a replacement mcor?
Is there an update mcor fo a 2001 DS cart

[scottyb]

What is the battery pack voltage (live reading) when the cart is running and clicking. Most likely the solenoid coil is dropping out because the pack voltage is low. When the solenoid drops out (opens) the load is completely removed from the pack which allows the voltage to rise causing the solenoid to close, which puts a load on the bad battery pack which causes the voltage to drop and the solenoid to drop out which causes the whole cycle to repeat rapid fire.

I hope this helps

[Papas 73Dart]

I will test the pack voltage running but the batteries were new last year when the clicking problem started