Tickover revs will not reduce

[Robert Leigh]

The RP has a standard Zenith 26VA carb. The spindle has no excessive movement up down and sideways but does move in and out by about 2mm.

I cannot get the idle revs to come down to a sensible level.  I have removed the linkage, the choke arm is not in contact with the throttle arm, the idle screw is not touching the throttle arm. Yet it still is idling at around twice normal revs. It picks up cleanly.

Presumably the butterfly is not closing sufficiently?

Any suggestions?

Assuming you have taken the carb off to follow up the other suggestions, you should be able to check whether the butterfly is seating properly by using a thin feeler gauge around the edge. If it appears to be off centre on the spindle it should be possible to re-position it by loosening the fixing screws and re-tightening with the butterfly held properly closed. If the problem persists you probably need a different body. I can probably help with this.