I posted on this subject a while back and thought I had fixed the problem at the last overhaul but its back. The slow run has tendency to be too high most of the time, usually if I wait long enough it will drop back to about 1,000rpm but it can take about a minute. Its not dangerously fast (around 1,300rpm) just annoying. I have the workshop manual and have hunted through it for help without success - the ISC has no adjustments and in truth although I had the tank off I could not swear I even found the damn thing!
Any thoughts? Is the ISC unit replaceable? Would that fix the problem?