Ask the Editors: Smoking, Screaming Zook
High idling is simply a matter of further fine tuning your carburetion mixture. Particularly the screw (circuit) responsible for idling. We would suggest turning out the idle screw so that it doesn’t rev so high upon initial start up. Find the balance where it isn’t revving to the moon but not so slow that it requires a blip of the throttle to stay running.
As far as the excessive smoking- you said to have replaced the rings but didn’t mention the piston itself. A smoking engine is usually a sign of oil bypassing the piston/ rings and ending up in the combustion chamber with the fuel and air.
Since the rings are fresh, there can really only be two other culprits in this scenario- either the piston is also worn out of spec and should be replaced as well or the cylinder itself is warped enough to allow oil bypass. A micrometer will tell you whether or not the piston is in spec easily enough. If it turns out to be the cylinder, your options include either replacing the head entirely, resleeving the cylinder or having it bored out (and honed) then running an oversized piston and rings.
