The hyster E30AC speed controller is a 10,000 ohm poteniometer.That is not where I would look for a problem though. Electric forklifts with solid state controls usually have only two problems with speed control. First is no motor torque and the second is full motor torque . Before you decide that the culprit is the speed controller; I would do the following checks : open control panel and check for stuck contact tip on the forward , reverse , and 1-A contactor . Also check for stuck contact tips on the Field weakening if forklift is so equiped . Low battery voltage is what causes the tips to stick . [You could have a battery problem , not a forklift problem ] . If battery voltage is ok , and contacts aren't stuck ; listen to the speed controller as you depress it . You should hear a click of a switch as soon as you start to press down ; and you will hear another click just before it hits bottom . If that is not the problem than it is a major problem . You will need a trouble shooting guide . Call your local Hyster dealer and ask the service manager for a copy of a trouble shooting guide . Most service managers are nice enough to fax or copy one for you.