78 Bronco issues


#1

My old 78 bronco is running which is more then I can say for most of the 78 trucks. It starts up fine but has trouble staying at an idle after a cold start. My boss suggested that it might be that the stock carburetor was switched to a four barrel souped up thing. Another guy suggested that it was getting too much gas. Yet another guy suggested it was because the guy that owned it before bored the 351 to a 390. I’m lost on this one. Any suggestons?


#2

The carburetor choke needs adjustment. A Haynes, or Chilton’s, repair manual would help even if it’s not the original carb.


#3

It’s probably not high-idling. There should be either a mechanical link or a vacuum diaphragm that holds the throttle open a little bit while the choke is closed-- sounds to me like that’s not working. I’d bet if you eyeball the carburetor you can figure out how your carb does it and probably figure out what’s broken, or else a service manual would help.