Carburetors are still somewhat of a mystery to me. It's been said that the word is derived from a french phrase for "don't mess with it". I doubt that's true, but it sounds good. I prefer computerized fuel injection.

So we have this van, 1980 E350, 1ton.... "Our Lady Of Perpetual Motion".
It's had a history of issues with the carburetor. The original carb was angry. At one time I assume it ran exceedingly well... probably about two years before i purchased her back in 2001. She ran pretty darn well then.

About 2002 we tried a new/better "remanufactured/rebuilt" carb after an emissions failure. The first "new/better" unit I sent back right away because it had a screw stripped in and not seated. The second I installed, but couldn't get the idle vacuum high, or the idle screws set well, and i never drove it... Sean got an emissions test done, passed, came home and, to my best recollection, said "put the old/crappy angry carb back on!". The new/better unit ran too crappy, and the old/crappy unit ran too better. The angry one passed emissions the next year. The new/better sat on a shelf and got shuffled to a Jeep, then almost tossed... apparently it was crappy. I caught it from the junk pile just last month.

So anyway, the angry carb died last year or so, quit running... black smoke, fire, the works.... Sean "rebuilt" it. I didn't want to do it because I like to feel a sense of accomplishment sometimes. It ran OK afterwords ...in comparison, so there was a bit of accomplishment. I was impressed. It had a dead spot when accelerating, and the choke quit working, but it started and ran. We were pretty happy.

Recently it quit. Well, it still ran, sort of. It wouldn't start unless you manually dumped fuel down the intake (Sean claimed that 10 or so minutes of cranking and pumping might start it eventually). And it would not accelerate hardly at all. One would have to baby the throttle, so to speak (different from throttle the baby).

I put the "new/better" carb back on it. Sean reminded me of how crappy it ran, so I took it back off and put the Cougar's old 2bbl carb on it. This one leaked fuel from the power valve diaphragm. Leak... more like a pressurized external spray of combustible fluid onto a hot surface. I fixed that. I pretty much only like fire if it's under control. Fire's cool, heh.

Then it ran pretty well... actually pretty great in comparison, but there was nowhere to hook up the PCV, and nowhere to hook up the tranmission kickdown rod (not that it was hooked up before). It also had a significant "dead spot" when accelerating. I decided i would try my hand at figuring out the problems with the "new/crappy" vs. the broken "angry/better".

New/crappy had 2 different size main jets. Big problem. Bad rebuilder. Very bad. No donut.
Main jets are a screw-in brass orifice to let fuel through, and the orifice is a different diameter for different applications. There are two, and they should be the same size as each other. Tuning a carb to a specific application involves, among other things, changing both jets to a larger or smaller (same) size. There are other brass fuel orifices too. I compared all to the original carb. All were different.

I put all the original size orifices in the "new" including the entire 'cover plate', and some other main stuff from the "angry".

Hooray for working suddenly stuff!!!
And i hooked up the transmission kickdown.
Double Hooray for stuff!!!

Our Lady runs 90% like a champ! I'm not messing with the remaining 10% chump. It has a slight hesitation off idle at low speed. meh (remember our french lesson). I keep the Cougar's carb in the van JIC. I have no confidence in this carb yet, but it does give the van the power it hasn't had in more than 6yrs.

So now that i have power to the engine and a shift kickdown, I can tell that the transmission might be dying... Hooray?
I'll change the fluid. It's been a tow vehicle, and the fluid is a bit brown and bubbly since the last time i checked it (s'posed to be red and, ummm, not bubbly).

edit: Trans flush did the trick. I did the old school flush... cooling line style. I disconnected a cooling line (to the radiator from the trans), ran it with a hose to a bukkit, and ran the van to flush the fluid. I got out about 4qt per run, and repeated until red.... still cheaper than a jiffylube flush.