First thing should have been to adjust the choke so it wasn't coming off before the truck was up to temp. Then you should have worked on tuning. You might be trying to tune out something that's not as bad as you think, or not there at all. If you think there's leaks at the base gaskets, get new gaskets, or pull them, wipe a thin coat of gas safe rtv on them, let them tack up, reassemble and let dry. That's just a band aid, but it'll get you running.
Personally, I'd get a rebuild kit and base gaskets and spends a couple hours cleaning and freshening it up before I bought one.

 

Well, I think I've had the most luck yet and the biggest, noticeable difference yet. I will attach a website that I found many weeks ago when compiling information on the Motorcraft 4350. It's the only guy that actually explains the metering rods and what they do in this amount of detail. My biggest problem to date, other than the erratic idle, was how rich it was running. The idle mixture screws couldn't tame the fumes that were coming out of this truck, so I got enough guts to tinker with the metering rods. The guy on the "Rodding Roundtable" website showed what it looked like at full "rich" and full "lean". So, when I pulled my apart today, I had about a 1/4 gap on the shaft, almost what this guy has on his. So I cut that in half and it's around 1/8, maybe a hair less. Put it all back together and she fired up and all of the things I had done to overcompensate (idle screw) had to be turned down because the high idle was too high. Let it warm up for over 5 minutes "IN" the garage and not once did I go, "MY EYES"!

So, I took a quick spin around the neighborhood. I have good throttle response and it just ran good. Got it home and hooked the vacuum gauge up. Went from 15-16 before the adjustment to 17-18 after. The good news is, I can turn it all the way to lean, I believe, without removing the whole carb from the truck again. The guy on the website actually screwed a hole in the top of his to be able to adjust it easier, but I'm not going to do that. I also removed the jets while I had the metering rods off to see what size jets were on it. They say "202". That makes absolutely no sense to me, so if anyone has a clue, please let me know. In my opinion, they were large, which may be why running the rods so lean has helped. When I say they look large to me, this is with no prior experience. I took some carb cleaner and sprayed through them and I don't think I hit anything but air, the fluid just shot right through. That's why I think they were large.

Here's the link to the site, for anyone else with the 4350 -----> Rodding Roundtable :: View topic - Motorcraft 4350 carb secret adjustments...

ALSO: One of the screws on the front of the carb that holds the horn to the body, is stripped. Was fine until today, but this would be the 5th time I've took it apart and who knows how many times before me. If I could source another bolt that is longer and find a nut that I could use, since it the kind that is exposed when you screw it all the way, would that be an issue. Kinda sucks, but luckily it isn't leaking to the point where is dripping or anything, it just got slightly saturated around that part of the horn.

Thanks!

 

yea i mean aftermarket. ill try the wooden edelbrock first. just weird that it will take throttle no problem with no load. then loaded it will actually shut off. pic for reference in case im missing something.

 

No that's not weird that's how it works, an engine only does useful work when being used. When was the last time that carburetor has been off, the Carter administration? Yikes.

 

Is that picture of the same vehicle we're talking about motomotard? Doesn't look like any cleaning has been done in a long time, unless that liquid covering the right front face is cleaner? Looks like leaking gas to me.
If it's leaking that much, then the diaphragm (or at least the gasket part of it) has failed and needs to be renewed.

Unfortunately for my feeble memory, I can't remember if that cover is the accelerator pump cover or something else. I remember also a cover on the bottom front in that area, but "accelerator pump" is what's popping into my head.
If so, then your lean-flameout could be a simple case of a failed squirter system. I forget if we talked about you looking down the carburetor while flipping the throttle lever and seeing two distinct lines of gas, but if not, you need to do that right away.

And so we don't thin out Keymaster's thread too much (although it is all related) you might start your own thread asking about possible issues with the carburetor and post up more pics like that one. Pictures are worth more than ever before (due to inflation and all, don't you know...) and can really help diagnose issues.

You can keep posting up here of course, but I'm thinking a dedicated thread might get some good answers directly and not confuse anyone as to which truck we're talking about (yours or the Keymaster's) as they glance through the posts.

Anyway, good luck with it. Keep plugging away and we'll keep trying to figure it out with you.

Paul

 

Maybe just get a different carb altogether and try it out.

And yes that really dirty item on the front of the carb in the picture is the accelerator pump

 

That would be helpful.

 

Not sure why Tedster deleted his post, but I thought it was a good one. And appropriate too, even with the little bit of sarcasm added in! Hah, not bad enough to ruffle any feathers I wouldn't think. Very appropriate here.
It's definitely a dirty carb. Which is at least partly why I was suggesting your own thread. 'Cause it looks like there's lots of discussion about it in our near future...

 

I did what?

 

yea yea ill start my own. all boats will rise ring a bell though?