Since messing with the vacuum advance made a difference, I suspect your timing is way off. Do you have a timing light? It sounds like it needs to be set.

You can leave the vacuum advance off for now and plugged. Get it running good and set the timing with the timing light. I would shoot for about 12 degrees BTDC. You can deal with the vacuum advance later, it's just for fuel mileage, nothing else.

 

Sir, with all due respect, the messing with the vacuum advance made no difference, no change at all, no high or low RPM, nothing has changed with the vacuum advance. I dont have a timing light, but I am sure I could rent one if need be, but like I said before, messing with the timing advance on the distributor did not make a difference at all. And since it is for only fuel mileage, what would cause the the issue I am having? I know the sprayer is working fine, and the accelerator valve is working properly.

 

Well decided to call Holley to see what they had to say. PSSHHHH the told me to increase the shooter nozzle for the accelerator pump discharge. Factory nozzle is .031 and it has that in there. This carb is actually oversized for this truck, so I dont see how it is that there isnt enough fuel getting into the primary side during idle. ESPECIALLY if the primaries are kicked in while driving.... I dont get it anymore. I am starting to get fed up with carburetors....

 

I would tend to disagree somewhat with the assertion that the "only" attribute of vacuum advance is for improving fuel mileage. It certainly does that (about 15%) but also, at least with stock motors it tends to improve the all around driveability particularly part throttle acceleration. It certainly can and should be disconnected and plugged for tuning and troubleshooting purposes though.

 

Well the tech at Holley said that the problem is not the VacAdv at all, but instead the sprayer nozzles in my accelerator system. The diaphragm is new, so its not torn or anything and it gets plenty of fuel delivery while idling, and plenty from idle to Wide Open Throttle, but when you slowly open throttle, as soon as you start moving the throttle open it starts to sputter and bog down until you get past that point. but if you increase fuel mixture, then it starts to run rough, if you decrease fuel mixture, then it idles rough, if you increase the idle screw it is beyond proper idle speed which it is idling at about 750 RPM when warm, about 900-1000 cold.

 

I was reading your posts and seeing what you did and didn't do, and I thought in one of them you could not get it to run at all, and then in another later after messing with the vacuum advance you had it running. What did you do to get it running?

Give a description of what you have now. Since you took the choke off, we know it's not going to run very well cold, so after you finally get it warmed up, how does it idle and how does it run?

 

csherill - it sounds like you are trying to combine (or are confusing the purposes of) the idle mixture and the accelerator pump, those are different entities and serve unique purposes.

 

No, I am aware of the purpose of the two, one is to adjust the fuel going into the engine during idle speeds before you get to the transfer plate, and you open up the throttle to use the main jets as a fuel source. The accelerator pump is designed to give a burst of fuel during take off to combat lack of fuel during the switch between idle and main jet fuel intake. Why I said the accelerator pump is because the tech from Holley said that I needed to upgrade the spray nozzle for the accelerator pump.

 

The battery was dead, I could not get it to start with that (sorry, I have a slow battery charger and had to charge it for a few hours.)

HERE is my problem. Truck starts and I have to keep pumping the gas and keep the idle speed above 1500 rpm or else it stalls and dies until it warms up.
I have tried to adjust the mixture screws, lean and rich and it runs better when it is about 2 full turns out.
I have tried to adjust the idle to about 1000 rpm to give the transition slots less time to do the transition. still no luck.
Driving down the road no matter what gear, no matter what speed it does great as long as I am accelerating middle way or more, or took my foot off the gas pedal completely. Once I go to ease on the gas to try and cruise. it sputters real bad.
I have the accelerator pump adjusted to where it still has .015's travel left on the accelerator pump at Wide Open Throttle.
When I press the throttle, I see two steady streams of fuel into the primary side of the intake.

It idles great when it is up to temperature, accelerates like a raped ape, and the only problem is when you are taking off with a slow RPM or when you are trying to cruise with the same rpm. Anymore questions please feel free to ask, I will try to be off and on all afternoon to get this little bug figured out.

Thanks to all my Ford family out there helping me with this.

 

So, it sounds like it doesn't idle when cold? What do your choke settings look like?

I'm sorry, I haven't really been following this issue real closely, mostly just breezing over things and trying to help where I can real fast.

I don't remember exactly where it happens, but 1500 RPM sounds to me like you'd be out of the idle circuit altogether... what does your choke do?

 

That, and the idle mixture screws won't work correctly at a high idle.

Everything needs to be mechanically "zeroed" so to speak before carb tuning can begin.

The butterflies should be 99 and 44/100ths closed at idle, ONLY the idle circuit is in play at idle.

The idle mixture screws are turned inward to lean out the carb as much as practicable, and then idle RPM raised back up as necessary. There's a little bit of a trick to this and it's possible to get the settings buggered three ways to Sunday. Not saying that's your problem here, but 1 and 1/2 turns out is the starting base setting and typically they will end up about a 1/2 turn from fully seated.

 

The solution to this problem is very simple; Get the choke working. What you describe above is exactly what the choke is for. It closes air off to the carb to create a richer mixture, and it has a cam that increases the idle speed. More choke equals more idle speed.

 

<p>I haven't read the thread closely enough to remember anything about the choke... but, yes, this is the choke's job, to set up the environment where the engine can run while cold....</p>

 

I think this is the one where he said he took it off. It sounds like he took the plate and everything out.

 

Hey there Chris, Thanks for skimming, but no I removed the choke plate, which here in NC doesnt get too terribly cold, and I usually use this as a trash truck mostly or a moving truck or whatever basically. I will post more at the end, just trying to tag everyone so far on this post.