Idling Speed Too Fast St4

Discussion in 'Technical Help' started by jbr, Jun 9, 2016.

  1. My ST4 starts well and ticks over fine when cold at about 1k.
    Once up to temp the idle speeds increases when I pull up at lights etc to over 2K.
    Anybody got any ideas?
    Could this be caused by valve clearances needing to be checked and adjusted?
    It has done almost 12K mles and is due a service.
    Can anyone recommend a competent mechanic in Herefordshire or Gloucestershire area please?
     
  2. It's possibly partly due to the valve clearances but much more likely to be down to a sticky throttle cable and injector linkages or the Throttle Position Sensor needs adjusting.
     
  3. Valve clearances out of spec are unlikely to increase the idle speed, they will more likely cause a poor tickover.
    Is the fast idle fully releasing. Check there is 1 - 2mm free play in the cable when it is fully off. The butterfly should be against the throttle stop of the horizontal cylinder when the fast idle is fully off.
    It could also be due to the butterfly spindles sticking but not very likely.
     
  4. Thanks
    Managed to slaken off the throttle cable a bit which seems to have resolved the problem
     
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