weber carbs

Jinx · #1 (**permalink**) 06-17-2004, 03:52 AM

i have 48 IDAs that run rich between 1000-2500rpms no matter how I turn yhe mix screw. The cabs are not driping fuel at a idle.I have a 50m idle jet in the idle jet holder?? the engine is 351 c /393 10.75comp......I live in south Fl,,west palm.any one know someone that works on webers in south or any where in Florida? thanxs....chuck.

cobrajeff · #2 (**permalink**) 06-17-2004, 04:13 AM

Enzo Alibrandi at Finish Line in Miami is a Weber expert. He knows his stuff, and has always been very helpful.

His number is: (954) 436-9101

good luck!

regards,

cobrajeff

Cracker · #3 (**permalink**) 06-17-2004, 05:57 AM

Jinx - Not to insult you but that's not how your carbs work. The idle adjustment screw only address' the mixture at true idle. Once on throttle it becomes the responsibility of the idle JET which is non-adjustable - just replaceable.

BB427 · #4 (**permalink**) 06-17-2004, 07:01 AM

Jinx,

What size idle jet holder do you have ?The idle jet and the holder control fuel up to about 3000 rpm. The stock holder is a 120 and the smaller the number the richer the mixture.

Brent

427Aggie · #5 (**permalink**) 06-17-2004, 07:15 AM

another thing that you have to look at is what type of air filter do you have on the carbs. If you have those little foam things that just slip over the horns then forget it you will never tune it right....

Brent is correct on the holder vs. jet. How do you know you are running rich? Have you put an Air/Fuel meter on it? I ask because you would think mine was rich at idle because I get a puff of smoke and it seems to be a little rich but on the dyno cruising at 1,2,3,4,5000 RPM we watched what it did when it swapped from the idles to the mains and it was interesting...65 idles I was rich 60's I was lean...now I have to stay at 60's and play with holders to see what I get

Just alot of fiddling to get them perfect.

Matt

Jinx · #6 (**permalink**) 06-19-2004, 04:35 AM

I have a 120 Idle jet holder, will try a 130 see what happens, also will try 45 jet as soon as they get here....I was told that the Ilde jet took you to 2500 to 2800rpm then the mains kicked in ?? if this is true I should be able to get my plugs looking good in that range then go to higher rpms to check the mains.....do the mains .air cor, emu tubs work at all under 2500rpm ..thanxs chuck///hey Atlanta if you had a brain I might ba insulted but then again dont argue with a 2 year old 10/4

Cracker · #7 (**permalink**) 06-19-2004, 05:22 AM

Hey Jinx - Your mains come in from 1,100 - 4,300 rpm's and then the idle jet takes over all the to 5,340 rpm at which point you must correct the fuel/air adjustment screw to set it correctly over 7,000 until you see black smoke coming out the pipes.

THEN... if you stick your nose in each barrel while having someone hold the throttle precisely at 5,000 rpm's any brains you have will be sucked out your nose. According to your last sentence which didn't make much sense you might have already tried this.

Jinx · #8 (**permalink**) 06-19-2004, 04:35 PM

matt..I drilled out the ilde holders just a tad, then had to put bigger jets 55 then 60s now Im back to the same boat mybe they just run rich??? when tou get on it after you clean the biuld up of carbon on the plugs the car runs like hell ,,,,black plugs sure does not make sense sould be atleast brown .put around town the car will load up ....race around youll get tickets....chuck

427Aggie · #9 (**permalink**) 06-19-2004, 09:08 PM

Ok then we get into something else on this...what size chokes are you running? What is the bypass valve size? You really really really need to put these on a dyno to tell where you are at..and I don't recommend drilling things out...then you get into problems that you may change the characteristics of the jets.

You would think mine was running rich...I get a big puff of black smoke when I get on it from just tooling around but on the dyno I am dead on from 3-6500 on A/F and I am a little rich on the idles .

Matt

Ford of France · #10 (**permalink**) 06-21-2004, 07:08 AM

You might want to check your float level before mixing and matching idle/holders.

FatBoy · #11 (**permalink**) 06-21-2004, 07:25 AM

For those of us unfamiliar with the finer points of setting up Webers, myself included, there's an excellent article under the Inglese add in the left-hand column of this page that explains in detail how Webers work.

Paul

Allan A · #12 (**permalink**) 06-24-2004, 12:18 PM

I would be interested to see what set up people are running with a 302/347 motor or 289. I have the same problem around 2800 rpm. The current set up is:

40 Venturi
Idle 80/55
Main 160 Air F7 155 Fuel

At Thunderhill an original 289/420Hp and a 351 were running the following, they both ran perfectly and are almost identical in set up:

289

? Venturi
Idle 120/70
Main 160 F3 165

351

30 Venturi
Idle 120/70
Main 170 Air F3 155 Fuel

Cal Metal · #13 (**permalink**) 07-02-2004, 07:56 PM

On the track, the stumble issue is probably irrelevant since most of the guys are running in excess of 3,000 rpms most of the time.

Allan A:

I doubt that the 351W was running 30 mm Venturis. If he was, his rpm range would have been pretty limited.

The best way to check on the stumble is to measure your air fuel mixture at all rpm ranges and make adjustments accordingly. If you want the stumble to go away real quickly, drill a third progression hole.

Cracker:

I think you have some of your data turned around. Idles @ 5,340?
Something doesn't compute.

Allan A · #14 (**permalink**) 07-02-2004, 08:15 PM

Yes, I keep hearing about the third hole, the plan is to send the car to Dan Fodge in Rancho Cordova. He has a set up for the drilling and we plan to dyno tune using the air/gas sensor.

You are right about the stumble, if you rev it up you would never notice it. Highway crusing is frustrating at this point,

Thanks,

Allan