Diesels when warm

[LeDevil]

Truck just started doing this the other day and I can't figure it out, when it warms up and I turn it off it diesels. Doesn't do it when it's cold just when it's warm. Truck has the stock hitachi on it.

[datzenmike]

Check your idle cut solenoid. During proper operation, when the ignition is turned off the solenoid cuts fuel flow to the idle circuit which prevents dieseling.

 

Too high an idle can also cause this by having the carb set above the idle circuit and drawing fuel from the primary circuit as well.

 

The solenoid is held against it's seat by spring pressure when off. In the on position a coil's magnetic field holds it open to allow fuel flow. With ignition on, disconnect the wire. There should be a pronounced 'click' from the valve. Remove and inspect for a broken spring or obstruction that doesn't allow it to close properly.

 

Is the float level set too high? This might cause a slight flooding condition which would provide fuel when ignition is shut off.