The timing can have an effect. (Only when the switch is on and the engine is running). If the timing is too slow, then the idle screw may be turned up to make the engine idle where it should. This opens the throttle plates a little more than they should be. Bringing the timing up to spec lets the throttle plates be closed a little more.
On more than one vehicle I have seen folks set the timing only to complain it wanted to run on after they worked on it. Set the timing back where it was supposed to be, then set the engine idle speed, and usually cured the problem.
Some of the newer carburetor vehicles the factories started putting idle speed solenoids to bring the idle up while the switch was on, and then to allow the throttle plates to close more when the switch was shut off.
This may not be the case here, just flat may be idled up too fast and the mixture screw a little rich.
But if the timing is slow it can also heat things up and do it pretty quickly.
Last edited by Roy Rodgers; 06/21/2011 1:41 PM.
