I have a weber 45 dcoe. Full open custom exhausts Msd coils. Rats eliminated. Eletric fan. Car idles great pulls hard from 1-2k bogs at 3k. And 4k and up is fine.

38 chokes
175 air bleed
180 main
7 e tube
I know.that weber have that hesitation. But does anyone know how to tune it? Every thread I've been to are 10 years old. Maybe be I need 36 or 37 chokes? My engine is Stockport. Any one Abe to.get theirs running perfect?

 

go to f8 tubes and larger air correctors put in 39 or 40 chokes take mains to 190 and you should be close just remember all combos are different. are you running a ar gauge, if not get one and see what it is doing when you data log a full pull and report back. have done many dell/webber tunes. webber is a lot more difficult to get to run properly as verse a dellarto that is a lot more tunable. why do you think rb used them back in the day

 

oh forgot to let you know the webbs run on lows speed jet until about 2800 rpm hope this helps

 

the weber has 2 circuits, the idle and the main. the idle circuit works on throttle position, and the main works on airflow.

the hesitation occurs when the idle circuit is falling off and the main isn't started yet, and its too lean (it is actually possible to have it stumble because its too rich, seems less common though)

there are two tests. the first one is to go somewhere flat where there isn't traffic, and remove the main jet stack. then drive around on the idle circuit, and you will immediately see where the idle circuit delivers fuel.

test #2, put the mains back, put the car in a higher gear and bring it up to around where the idle circuit stops. floor it. it'll run for a second on the accel pump, and then if its too lean, it will stop running.

so there are two ways to fix the stumble, 1 is make the idle circuit work to a higher rpm, and the other is too get the mains going sooner.

on a dcoe, the idle jet has an air bleed, if you make this smaller the idle circuit will work to a higher rpm.

or you can change to a smaller main air corrector, this will get the main circuit working at a lower rpm.

or you could do some combo of both.

 

You need at a 50 increment between air and main jet. For example, for a 200 main, your air jet should be no more than 150.


Also start with f11 etube and 55 idle jet then increase the idle jet until the usual 3000 rpm stumble is gone....then play with different size venturies...but if its my call, i will run it without venturies

 

Alright I'll grab a. F8 and a F11 and bigger jets

 

i agree, thats a great starting point.

 

Ok just got some e tubes and jets hopefully I get it running good

 

J9fd3s is most Likely correct but don't overlook timing either, this will cause similar problems and you could be fighting a combination of both.

 

Alrite guys I got the jets all good. Now I think my fuel pressure is the problem it keeps on dropping, maybe electrical problem? I set it to 4 psi drive it around the block and check it it is back at 2.5. My for is a Holley. Car idles fine. The transition from idle to main circuit. Is smooth but it feels sluggish

 

2.5 psi should be fine for a weber. 4 psi is a little on the high side. Are you tuning with an A/F gauge?

 

It's always been my experience that a stumble indicates too rich not lean. I've been running a 50f8 with pretty good success.

 

you can stumble either way if its just lean or rich for a second.

i find it really hard to tell rich or lean without a reference point, which is why the o2 sensor helps

 

Thanks guys if my buyer doesn't take the car this weekend a wideband is on the way! Thanks again!

 

Wow! When I first put the weber on I was thinking to myself what have I done. The driviability is terrible why would anyone do this compare to the Nikki. I finally got my car tuned. With no bog and man that thing pulls HARD! Thanks guys! I couldn't have done it without u guys!

 

So what were the final jet sizes and everything in your carb. I have the same issue with the hesitation and also seem to have no top end.

 

38Choke
175 main
140 ac
F2 e tube
60F2 idle

 

Also check your fuel pump and regulator and super tighten all you fuel line clamps. That was my main issue.

 

Where did you get your parts from? I was looking on CARBS UNLIMITED INC. carburetors including Weber Edlebrock Holley Quadrajet and didn't see F2 idle 60 jets.

 

http://www.fastroadcars.co.uk/shop/i...iewCat&catId=5

What's your jets right know?

 

I've gotta check that yet. I know when it was first done I didn't have issues, so maybe I just need to give it a good cleaning, but figured I'd get more info since I'm at work and can't do anything to the car right now.