Fast idle cams

Hi everybody. On my completely stock 74 258 with stock carter carb, I am having an issue with the fast idle cam. It seems as thought the fast idle cam never disengages, the choke plate opens all the way, but the motor is constantly idling higher then it should. The carb is freshly rebuilt and there is no binding on any linkages. Does anyone know how to troubleshoot/adjust this? Again this is a stock 258 with the carter YF 1 barrel carb.

 

I'm not that familiar with the YF, but doesn't it have a bimetal spring in a black plastic cover that pulls off the choke plate? I'd guess that the same spring unloads the fast idle cam if all is correct and functional.

There's a section about YF fast idle cam adjustment and the choke unloader in my '77 TSM - I don't have time to copy it right now, but I'd say that's your best source. There is a choke rod to the fast idle cam that should unload the cam when the choke plate is open and you open the throttle.

 

BTW there's a '72 TSM on the web at www.c104.net - that will be almost the same as the 1974 TSM.

 

It is possible to put the cam on backwards. Ask me how I know. Check and make sure this is not the case.

 

Actually I'm all set. The way to adjust the fast idle cam is to bend the linkage outward torwards the drivers side. No need though. I just adjusted the choke via turning the choke cover to a leaner setting. This subsequently pulled the fast idle cam up and allowed curb idle to take over. Thanks for all the input.