The butterfly is adjusted so that it just closes on a cold engine. The new choke pull-off at start-up is perhaps double the 1/8 inch or so that's recommended, but the engine seems to run smoothly. At start-up, the RPM's jump to 1400-1600 and stay until the throttle is blipped, then the idle falls to 500 or so, well below the recommended curb idle and wants to chug a bit. When warm, the idle rises to the appropriate curb idle at 700 or so. I'm still having cold start problems too--five pumps before the engine will fire. Choke or choke pull-off problem? General advice?

JamesC

 

I use the elec. choke adjustment to set the choke operating range (how cold before it comes on, how warm before it goes off). I use the choke pull-off to get the best idle cold, and readjust the fast idle afterwards. I would start the car when cold with the choke on, and play with the actual choke flap (open it a little, close it a little by hand) and the idle should get better and worse. Adjust the choke pull-off with the screw to the spot where it idles the best. If it idles too high, bump down the fast idle speed. Moving around the elec choke will adjust how fast it comes off of fast idle. Might take 2 or 3 times first thing in the morning to get it straight. This might help with the hard start problem also. Do the carb bowls drain down overnite?

 

I've played with the butterfly and adjusted it to where the idle seems good, though as I say, the butterfly is open very wide considering the recommendations (3/16 to 1/8 inches). I guess I really figured the choke was going off too fast and causing the "slow" idle difficulty. Is that a possibility? Fuel in the bowls in the morning.

By the way, the solenoid problem turned out to be the relay along with small adjustment mistakes on my part.

JamesC

 

Try twisting it a little to make it stay on longer. Just be sure that when the engine is warmed up it is completely off.

 

I assume I twist in the direction of the rear of the carb?

JamesC

 

You twist in the direction that closes the butterfly.

Also sounds like you need to back off the pull-off adjustment as well. The first throttle blip should only move the fast idle cam down one notch. If the pull-off is opening too much, you'll drop down too far on the fast idle cam.

 

Fun and games. After rereading some searches, I noted that the butterfly was supposed to "snap" shut. Mine was gently closing and not fully at that, at least not every time. I sprayed carb cleaner on the various linkages, inside and out, readjusted the butterfly with a bit more tension--and lo and behold, the butterfly not only snapped shut, but the car started with one pump of the accelerator. The choke was fully open in three or four minutes. Adjusting the pull-off to a more rich condition, however, made the car want to stumble badly (had I not given some throttle, it would have died), so I'll have to mess with that a bit more. Though my first experience with carbs was the mid-sixties, when I had two single barrels on a straight-six 1954 Chevy, they're still a mystery of cosmic proportions to me .

JamesC

 

Glad you've got it figured out (more or less). Like anything else, once you know how it works, all you've got to do is play around with it a little and you will get it fixed.

 

Well, I hope I'm on the right track anyway. I think I'll back the pull-off off a quarter turn or so for the next two or three days and see what happens (a half turn will get me to where I was before).

JamesC

 

If the choke wasn't fully closing, the fast idle cam wasn't going to the highest notch, either. We all assumed in our replys that the choke was fully closing and not gummed up. Shows once again that when we assume, it makes an "***" out of "u" & "me"...