carb idle, stalling, 1960 Lark

[Guest bobgould]

1960 Lark 6 cyl stalls when I come off the highway carter AS carb ,Idle is a little erratic by 25 rpm or so runs beautiful other than that, any suggestions? I did rebuild carb.

Edited May 14, 2015 by bobgould (see edit history)

[1927Chevy]

I am thinking float not adjusted right, other than that when rebuilding did you soak in something like a heated ultrasonic tank, I have a small one for small carbs and it works wonders, cleans all the jets and seats and idle tubes.

Edited May 14, 2015 by 1927Chevy (see edit history)

[carbking]

Possible the idle mixture control screw is too far out (rich), which would cause the curb idle to be set with the throttle plate completely closed. A run on the highway will cause the mixture to lean out, and if the throttle plate was completely closed, would cause a stall at idle.

 

Jon.

[Ltc4748]

You did not mention how you set the low idle mixture. You should set low idle to spec's with the speed screw on the throttle and then adjust the mixture screw(s) ( 1 screw on a single barrel carb and 2 screws on a two barrel carb ) in or out whichever way increases the engine RPM. reset the speed screw and then turn the mixture screw(s) again to get the highest engine rpm's and reset the engine speed It should get to the point no matter which way you turn the mixture screws(s) the engine speed will go down, this will have set the mixture correctly or what is known as peaking the carb. If the mixture screws are turned fully closed or are coming out of the bore 5 or more turns then the carb is not working correctly and should be checked for the problem associated to where the mixture screws are in or out.

[1927Chevy]

Great info Guys! Very interesting information!