The VW Idle Shut-off Valve is a smog control device that prevents fuel from spilling into the carburetor when the car is shut off. The idle shut off valve will not keep a car from running, if you suspect a faulty idle cut off valve is causing an issue with your carburetor, unthread the valve and plug the threaded hole. If the issue still exists, the solenoid is not the problem. The needle style fuel cut off valve fits 1968 through 1970 Beetles, 1968 through 1970 Karmann Ghias and 1968 through 1970 Type 2 Bus models. The idle shut off valve is also referred to as a cut off valve, cut-off valve, idle valve or idle cut off valve.
The Idle Cut Off Valve is only a smog control device. It is designed to shut off the idle circuit when the ignition is turned off. It can cause problems with an engine idling but is not normally the cause of carburetor problems.
You can see if the valve is causing the problem by unscrewing it from the carburetor. Then hold your finger over the hole on the carburetor while a friend starts the car. If the car starts and runs fine, the valve was the culprit. If the same problem exists, the valve is not the cause.
California Prop 65 Warning:
Please Note:The information listed below is for stock, unmodified VW's manufactured for sale in the US. VW's are commonly modified and very often parts from another year VW may have been installed on your car. California Pacific JBugs is not responsible for any errors if your car has been modified in any way.
To test your cut off valve, disconnect the wire and unscrew it from the carburetor. Plug the wire back on. Touch the metal body of the valve to the carburetor or any metal on the engine. Have a friend turn the key on and off repeatedly. The needle should move in and out as they turn the key on and off. If the needle moves, it is good.
On a side note, for off road, racing, close coursed or non smog controlled areas the valve can be disabled and not used at all. We do this all the time on our off road race cars. The valve can be unscrewed and a threaded cap can be threaded into the port to seal up the hole in the carburetor.