Engine Revs Fast After Warm - Possible Causes?

[jb3t]

My 1978 C10 Big 10 runs very well. Starts right up, idles well, and runs great. However, I have noticed that after driving it for a few minutes, the engine appears to rev. Example, I will pull up to a stop sign and it still wants to go. If I slip the truck in neutral, it will rev pretty high (no tach so I don't know RPM). If I pump the gas while in N, it may settle down. It's a bit of a safety issue that I need to figure out. It's a pretty high rev. Like I'm pressing on the gas and break at the same time.

Any idea what may cause this? Hopefully its a simple carb fix.

[77 350 Shorty Wide]

Good afternoon, Check to see if the carb. is hanging up on the fast idle cam.

God Bless, Terry

[Eyegore]

Were there any fords nearby??? only natural!
Mine did the same, follow 77 advice.

[jb3t]

Thanks... I'm no dummy, but I am no carb guy either. Can you give me a visual of where that is? I can take it from there. Standard 350 engine.

Your help is greatly appreciated.

[cadillac_al]

On the opposite side of the carb from the throttle lever is the choke and fast idle cam. It would be good to familiarize yourself with how it works. As the choke closes it moves the fat idle cam to raise your idle. It sounds like your choke isn't opening all the way or the fast idle cam is sticking or something. If the choke looks all dry and corroded then a little spray should help it to work smoothly. good luck.