I’ve been messing with this again. The problem is still there.
The only thing to concentrate on is pulling the throttle to right off idle position and holding it there.
THe transfer slots are going full force. I can look down and see them working. The engine is stumbling here. They are air and fuel. A fine spray.Are you by any chance confusing the transfers and the mains? The transfers discharge below the blades at 1700rpm, I don't think you can see them. And at 21 inches idle vacuum,it's probably too early for the mains; they should be dead or near dead at 1700 no-load.Or are you confusing the transfers and the accelerator pump discharge nozzles; If the check plunger or ball is missing from just underneath of them, then your high vacuum can pull fuel out of this circuit.Did you once mention finding a ball after you tipped the carb over?
The accelerator pump would not be doing anything. Correction;SHOULD NOT BE
The power valve would not be engaged because........The engine is held by me to a position of right off idle. Correction; the PV SHOULD not be engaged. It discharges from the main circuit, same as the mains, so if you see the mains discharging at 1700 with no load, then it is entirely possible that what you are seeing, is a PV discharge.
The only circuit that would be working is the transfer circuit because the accelerator pump has done its job.Again; SHOULD BE
Where could extra air be coming in. The vaccum ports are all blocked off. I mentioned this once before; flip the PCV out of the valve cover and seal the covers. Then put a vacuum gauge on the dipstick tube. There should not be any vacuum there. At 21 inches idle vacuum,I doubt you have this problem.
Could it come into the intake or.....power brake booster connected straight to the intake. The booster should be plumbed directly to the intake, usually at #8 runner, and the PCV on a separate line to the front of the carb, and exits under the throttle plate there.
The Vcan line SHOULD be plumbed to the spark port, which SHOULD be dead at idle. This port will increase in vacuum signal as the throttle opens ,BUT should be dead at idle and may not begin to pull significant vacuum until 1500rpm. or higher. This action is heavily dependent on the engine load and TIMING.
I've said this before, but here it comes again;
Disable the Vcan, Crank the idle speed up into the crap-zone with either the fast-idle cam or the speed screw. Pull or push the distributor until the rpm peaks, then readjust the idle speed into the crap-zone. You now have fully and completely ruled out a timing problem. Readjust the mixture screws as may be required for best quality of idle at that rpm.Put a timing lite on it and watch the strobing, looking for dropped sparks or any monkey business going on there.
Now, grab your flashlight and shine it down into the venturies. You SHOULD NOT see any fuel discharge anywhere. The pump nozzles should be inactive and the mains as well. The only fuel flowing SHOULD be from the transfers, which you should not be able to see, as the entire slots or almost the entire slots, should be below the plates. If any portion of the slot is above the plate, it should be inactive and dry.
For the heck of it put one finger on top of each booster to destroy the signal there. The engine idle quality should not change. If it smooths out, then there is your problem.
Pulling in extra air as the throttle opens up and air velocity is increased.
If that’s the case. Wouldn’t idle vacuum be really low. 21” is a pretty high number.
It seems like this problem is extra air coming in right off-idle into the transfer circuit. To me it seems like waay too much fuel.
It might be masked at idle by tuning it out and pulling enough gas at higher rpm to mask it there as well. Masked because the transfer port exposure is really small or non-existent. Have you set your T-port sync?
Could an intake leak cause a problem like this? I don't think so
