Engine: 61 lark Run ON

[drnittler]

On my Lark 6 cylinder sometimes it wants to run on after I shut off the ignition. Why would this happen? Everything has been rebuilt and timing in dead on.
I am the guy who asked about Champion plugs because they were flooded.
Thanks.

[41 Frank]

Try reducing the idle speed first. Many are under the impression that timing causes run on, well the fact of the matter is that when you turn the key off there is no more timing because there no longer is any spark! Run on can also be caused by hot spots in the cylinders caused by carbon buildup, unlikely, since you say everyting has been rebuilt.

[drnittler]

That is true I never thought of that. Thanks

[drnittler]

Latest concerning the run on... I dropped to idle on the carb. I sort of prevented the run on a while. Now when the car is cold the idle is too low and I have to rev the car up and keep it there until it warms up; or if I set the idle higher, then I have to run on again. (This is a six cylinder with the automatic).
Can the wondeful ethonal gas cause these problems?
Thanks.

[Dick Steinkamp]

Latest concerning the run on... I dropped to idle on the carb. I sort of prevented the run on a while. Now when the car is cold the idle is too low and I have to rev the car up and keep it there until it warms up; or if I set the idle higher, then I have to run on again. (This is a six cylinder with the automatic).
Can the wondeful ethonal gas cause these problems?
Thanks.

I am not sure how the carb on a 61 6 is set up, but on all carburated cars that I have worked on, there is a stepped cam on the choke linkage that increases the idle speed in stages based on how closed the choke is. Make sure this cam is in place and working properly.

[KOOL R2]

The run on is more than likely caused by the idle speed screw being adjusted to raise the engine speed which was done to compensate for an incorrect setting of the idle mixture screw. I suggest turning the mixture screw counterclockwise about 1/4 to 1/2 turn and see what happens. I think that you have been running it too lean

[Ron Dame]

Is this a Carter AS carb like I'd think? If so, the fast idle speed for when the choke is on is an adjustment (really bending) an L shaped link that goes between the throttle shaft and the choke lever on the back of the carb. Then you can get both a proper idle speed and enough fast idle when cold. Close the gap between the two ends, maybe 1/16" at a time until you are happy. In theory, if you take the carb off the engine, you can make a more precise adjustment according to the shop manual.

Latest concerning the run on... I dropped to idle on the carb. I sort of prevented the run on a while. Now when the car is cold the idle is too low and I have to rev the car up and keep it there until it warms up; or if I set the idle higher, then I have to run on again. (This is a six cylinder with the automatic).
Can the wondeful ethonal gas cause these problems?
Thanks.

[Flashback]

Try leaving the auto. transmission in gear, turning off ignition, and then going to park. This is not the solution, maybe, but it helps til other things can be checked.

[SN-60]

Flashbacks shuting the engine down in 'drive'----a good old tip that usually always works. but I agree the idle speed means a lot in this situation. (You might also try some combustion chamber cleaner)