Hello

I have many SP's and throttle pots are one of the main things that fail.

You should remove the cover on the operator platform. Plug handset into the machine. Check what Chevotaman said. Also check and make sure the forward and reverse switches are set properly. Whenever I calibrate throttle pots I always mechanically set it on the spur gears first while watching the voltage on the handset. When I'm satisfied that it is in the proper position mechanically then lock it down. Only at this point can you calibrate it digitally with the handset.

The throttle pots DO have a mechanical stop in them and if you don't mechanically set them in their centered position when you go to use the throttle grip the pot will max out and jump a tooth on the spur gears or wear the spur gear out(they are plastic), then your pot will be out of range again.