weber carb troubles
 

Hey guys, I have a 12a in which i'm running a blowthrough carb setup on. The carb i'm using is a weber 45 dcoe. Now, my setup is all together, I have my timing set exactly where I want it, and the car starts and idles like a champ. So i figured today, i'd actually try to take it out for a spin. Wrong. I backed it out my sloped driveway, and tried to drive it back up the driveway just to see if things were working well. As soon as I opened the throttle and eased off the clutch, the engine chokes down, and it goes as lean as my af gauge will show. Put it in neutral, and try to rev it up, but as soon as I hit the gas, the car goes from stoich/rich to extremely lean, chokes down, and then stays lean for a few seconds before going back the semi-rich. I've checked my fuel pressure, which is staying constant, I had gas in the tank (haha), my accelerator pumps as squirting out plenty of fuel(i also dont think it's the accelerator pump because the car stays lean as long as I have my foot on the gas, doesnt go back to rich until i let it off, and it goes back to just idling). I'm running 230 main jets, 160 air correctors, and f11 e-tubes if that helps. Anyways, i hope there's a carb guru around who might have some answers, hopefully this will be the last problem on my setup. Thanks for the help

-Jake

I have the same problem, hopefully someone can help us... I think its just all about tinkering with jetting... But my car won't rev past 2000-2500 rpms...

no, not the jetting. actually your air bleeds, e tubes, and jets sound dead on. how many turns out are your idle screws?

My idle mixtures screws are backed out about 1 1/2 turns. I can't figure this one out a bit. It's like there's no gas whenever the engine is uner any kind of load, or if I'm trying to rev it up quickly. But, it will hold whatever rpm I want, if I extremely slowly press down the throttle. For some reason, it sounds like the idle circuitry is fine, hence at only partial throttle, the car will run fine. But I'm guessing that as soon as the throttle plates move enough to start drawing off the main jets, it gets 0 fuel. Actually, that sounds like a damn good reason for my problems. if this is the case, what could be the problem here?

what is your foat level like?

just an out there guess but your level could just be peeking over your idle jets

Is gas getting fed through the boosters? Sounds like there's trash in the circuit clogging up the fuel's path.

check your fuel filter bro, and my 45dcoe is backed out 3 turns... so yeah.. but im not turbo and my car runs a little rich..

back out your idle screws atleast 3 turns and crank the fuel pressure up to 8psi (base).

nimrodTT - that was my guess, but I've cleaned and rebuilt the carb, and i thought I would have gotten everything out of the circuits. hmmm. It was my first time doing a rebuild, and I'm sure something could have gotten stuck in the circuit somewhere. I'm actually looking to buy another 45 or 48 dcoe, anyone have one? Mine's beat up badly, there's a crack in it i had to repair, and in genereal, looks like it's had a rough life, and a good deal of shoddy work done to it. Anyone have an ok weber sitting around? :D

anyways, I'll up the pressure some more, and back out the screws. If that doesnt work, I'll be back here tomorrow, whining some more about it. maybe I'll post some video of the old a/f guage next to the tach, so you guys came see exactly when it's going lean, and fully understand what's going on. Cause yea, i need to get this problem taken care of, and get this setup on the road... cause my setup is pretty badass ;) haha, i can't even compare to some of the cars on the board, but I've got pride

for the carb, go to www.piercemanifolds.com brother