Good Morning and Happy Labor Day!
So here's the question: Why all of a sudden must I close off the dash adjustment 100% to get the car to start and run? Finalizing the "frame off" restoration, excited about the first drive, cranked it for half an hour! Nothing! By luck I began playing with the dash adj and when fully closed it sparked right up, and if you move it a touch to the left she wants to stall and die. Any Ideas?? Thank you so much
Carburetor is a fresh professional rebuild, has about 20 miles on it.
I think something is wrong with the carburetor. It should not even run closed all the way. . Maybe incorrect main jet for the application, or a missing gasket, or something is not tight inside?
Question the rebuilder first. Could have the wrong adjusting needle installed ?? .... one from a Holley Vaporizor ?
I'll send a message in the morning. Hate to bother on a Holiday. Thanks
Possibly a vacuum leak?
You are getting too much fuel to air ratio. Something leaking in the needle or seat.
If the locking hex threaded bushing has been tightened when the needle was not fully installed then it can pinch closed and make it seem like the needle is "bottomed" when it is only hitting the hex topped bushing shoulder and not a "true" bottom in the seat. To fix this and/or confirm it is happening, take a felt pen and mark the thread at the hex to note what is the current "bottom" then take the hex nut and needle all the way out and screw the needle into it when it is not in the carb and see if you are hitting a false bottom in the hex fitting itself. If yes then spread the hex fitting by any means reasonable including just threading the needle all the way past the end of the bushing while the bushing is out of the carb. When it is all correct, reinstall the hex bushing finger tight only and insert the needle in to the "true" bottom in the seat and then back off 1-1/2 turns and snug the hex just enough so the needle won't move. then try again.
If it has one of the new replacement adjustment needle rods the vendors are selling it is probably not threaded as far as it should be; can't thread in and close the needle jet. I can't imagine they don't know about it by now, the last ones I ordered months ago were all short or threads by about 1/4 of an inch. It's an easy fix if you have a 1/4 x 32 die, not so easy if you don't.
When my new brass Holley G is ready please ship it ASAP....I'll send you this one to check out for me. I wouldn't dare tear it down without having a backup in case I foul it all up. I don't have a 1/4 X 32 die and I don't feel I have the expertise to dismantle and rebuild the carburetor. It is a brand new rebuild though, so maybe it has the aftermarket adjustment needle rods as you describe.