Hi Everyone,

I recently purchased a used 2003 Caterpillar GC20K (Serial Number: AT82D01065) and I'm am having a problem with a high idle. When the machine starts it takes a few seconds and the idle raises up about 1500 rpm (I'm guessing as it does not have a tach). Not sure if its related but if the machine sits (ex: overnight) it is difficult to start. As you will need to turn the motor over 4-5 times and it will eventually start. There are several other forums related to this issue and most seam to point to a vacuum leak. Reading those other posts I have already checked the two vacuum hoses that go from the throttle body to the distributer and the computer and they are correct, connected, and not leaking. Next to the regulator/converter there is a vacuum solenoid that has three hoses; one hose off one side, and a elbow with two hoses off the other which I'm assuming bypasses or redirects the vacuum when the solenoid is charged. When I got this machine that solenoid was hanging there and those three vacuum hoses were disconnected. Does anyone have a vacuum diagram for this machine or can confirm where those three hoses go? Additionally, I can tell that the converter/regulator was recently replaced as it looks considerable newer that the other components. The regulator is a Impco J (P/N JB) can anyone confirm that is the correct regulator? Does anyone have or know where I can get a service manual? Also I have removed the throttle body to make sure everything is moving freely, and everything seemed to be fine.

Not sure what to check or where to go from here. Any advice would be appreciated.