Fast idle after engine is warm..can someone give advice plz

[Pmac]

I haven't tried that yet as I'm inexperienced with carbs but I'll check it out. The problem just started after it got very cold here -40+ C. It was working fine a couple days ago. I believe it's a factory carb for the 305 121000kms

In my experience this it likely the fast idle cam has been sprayed with some lube and is sticking - I have seen this many times in cold (it is -40 here this morn) or warm temps; spray the cam/linkage with carb cleaner and move the linkage - until it is completely free when the choke plate is completely open - do not adjust the choke or linkages if it is starting in -40. Qjets when set correctly will start in -40C and +40C conditions. The linkages must be completely clean.

 

[BillK]

It sounds like the choke is not working properly. There is a black wire that goes to the choke heater (round black part) on the side of the carburetor. Unplug it from the choke heater and check to make sure the connector is not corroded. Clean it real good and put it back on and see what happens. The wire should have 12 volts going to it when the ignition is on. Its pretty rare for the heaters to go bad.

If the choke is opening all the way then try spraying all of the linkage on the choke side of the carb with carb cleaner. it might be sticking too.