Hi All,

1977 20R pickup. I have had rough/long or no start up when cold for quite a while now.

I either flood the engine in the mornings or when it does start it sounds like a misfire (subaru sounding) wont change with rpm just sounds very rough the engine violently shakes. It wont high idle upon cold start either, it just shakes at low idle and stinks like raw fuel. Carb mixture screw is set per another threads method.

After it warms up it idles just fine and smooth no raw fuel smell either. (only stinks like fuel on cold start and warm up). Also after the first drive of the day it starts just fine the rest of the day, but still has the rough idle until it reaches operating temperature.

I have checked for a vacuum leak with no luck and am starting to get frustrated. I have changed my fuel filter, checked my timing, installed a GM ignition control module and a electronic distributor from an '80 20R, choke is working properly, all this with no help to my cold start issue.

Is there anything else I need to check that I am missing?

Thanks in advance.

 

maybe the carb is just plain old and needing complete rebuild.
when i say complete rebuild, i mean complete with new bushings and all.

probable just a vacuum leak.

next time you start it cold, spray some carb cleaner around it and see if it stabalizes, if so, you have a vacuum leak. after that, its just time to isolate it and fix it.

 

What that guy said, your carb could be just old. I was having problem starting my 81. So i made sure to switch to 5w-20 oil and I cleaned up all my battery connections and made sure everything was tight. Give a couple pumps of the before you start it and now its starting is sub zero temps with no problem.