polara66hardtop
Senior Member
It is recommended to set timing and adjust the carb with all vacuum disconnected.Once that is done, if the engine acts out once you plug in the vacuum, that will tell you something.
Ever seen a 2bbl carb with only ONE idle mixture screw?
- Thread starter FinallyGot1
- Start date
FinallyGot1
Member
Well I figured that, since the timing was correct before I did any of this and I didn't touch it, then it should still be correct.
Just realized one small but significant change: vacuum advance WAS connected to ported vacuum before the carb swap whereas NOW it's connected to manifold vacuum (only choice available with this carb).
Good news is I got it to idle (relatively) smoothly. Bad news is as soon as I touch the gas it sounds like there's a big gasp of air and the motor tries to die. If I let off quickly it recovers and returns to a nice idle.
So the timing IS off I think. Should've disconnected the hose methinks.
Sorry. I'm thinking as I type.....
Update: Tried it with vacuum advance hose disconnected and plugged. No change whatsoever. Dangit. If I do manage to get it to rev up, it hunts & surges. Won't maintain a steady speed. Same as before.
Last edited:
polara66hardtop
Senior Member
Yikes, If I was close I would love to look at it. It's time for a vacuum gauge and timing light. I use the light to watch what the timing does as I rev it up, and the gauge will tell me what that big gasp of air is about. Manifold on a stock engine is all about consistency. 14 Inches steady is better than fluctuating 10-18.15-16 works, 18 is outstanding. That carb Isn't usually that flighty, unless There is an Internal problem.
FinallyGot1
Member
I'm thinking a botched rebuild is to blame. My fault for not doing it myself.
Could it be vacuum leak(s) due to something going funky with the bathtub gasket?
polara66hardtop
Senior Member
An incorrect carb gasket, or a PCV hose outlet. The center gasket, leave the car Idle, and spray carb clean between the top,middle and bottom, and see if you get a reaction. That needle could not be moving up and down properly. Depending on what result you get, you may have to take the carb apart. Once I found on a rebuilt someone forgot to even Install the needle in the carb.
FinallyGot1
Member
Have to try it tomorrow. I work 3rd shift and it's time for my nap. Thanks for the info.
Hopefully some better progress tomorrow.
The Horvaths
Young man with a cowboy hat
Do you have the means of checking the vacuum needed to get the timing advance canister to pull all the way in? It should be a couple of inches Hg less than your cruise vacuum. If it has a hex shaped can, it is adjustable. A 9/32" Allen wrench can be inserted into the hose barb and you can check where it's at now by counting turns in to stop. That will be lowest vacuum setting. If you don't have a gauge, back it out 2 to 2.5 turns and try it there. You can always put it back.
FinallyGot1
Member
Very cool! Didn't know there were adjustable cans for Mopars. That's a very handy tuning tool. Thanks a bunch for the tip.
FinallyGot1
Member
BINGO! Thanks a bunch for the clarification. I think I get it now.
Similar threads
