Racing engine - High Tick over

[Roger_Kern]

After a long journey the throttle appears to stick and the engine will not idle. The engine revs at around 1000 to 1500 rpm. This makes going from forward to reverse quite alarming! This only happens when the engine has been running for say over one or two hours. I have cleaned and greased every joint on the throttle linkage. Any clues? I have not found out how to adjust the idle speed either.

 

[davealtree]

Racing engine

I used to find that my Golf GTI used to race if the mixture was too lean.  That colour are the plugs?  That will indicate if the fuel  it is too rich (black) or lean (burnt/blistered).