Resistance settings of Pot Box

[vnt90]

I cannot find serial number but I believe the par car is 1990,s. 36v 3 solenoids. The cart started studering. Measured pot box resistance and it showed inconsistant resistance as I moved it. I replaced the potentiometer with a 0-5kohm. Since the arm on the pot box only moves about a 1/4 turn where should the full throttle resistance be set. I have it set for 3k ohm on full throttle but no movement fwd or rev. I hear the relays working but no movememnt. The pot box is the only thing I changed.
thnks in advance
vnt90