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I need to know what the recommended setting is for the Fuel/Air mixture screw is. I know the timing is slightly off, and I plan to adjust that, but I can tell that I'm running really rich, and I wanted to know where it should be set at, and then I can adjust it as needed from there.
See my statement in shoutout to set the carb up - are you running an electric pump or a mechanical - if mechanical, a fuel pressure reg with feedback will be needed because the mechanical pump pressure is too high and will overpower the needle valve.
Yes I did see it, thank you. I'm running a mechanical pump. Do you have a fuel pressure regulator you recommend?
dude, good luck i printed like 15 different weber tuning articles used the weber manual have every idle jet primary and secondary, every air corrector from like 135 and above and every main jet from about 195 and below. went through them all, best advice i could give is from one article tune each circut indepedently starting with idle circut, main, and then air corrector and according to article if it bogs, hesitates, or flattens out it is from a LACK of fuel not too much opposite of standard carb like holley or carter. adjust carb to where motor runs best not to what it "should be" according to whatever tuning article you are using. Because if that was the case i would have a submarine good for sea level and -3000 ft below.
S true - Geronimo was tuned by my friend that tunes all kinds of cars with webers, so he eliminated a lot of the guesswork for me. Another difference with a weber is that the flow rate is more important than the pressure to the carb - it needs more gph to work right.
Same as every other carb on idle air/fuel adjust: screw it in till it seats and back it out a little. Now it should be rough. Back it out till the idle smooths out, then keep going till it gets rough again. Now go back in till it smooths out, keep going in till it roughens up, then back out a little. You should find a "sweet spot range" that your engine likes. Factory settings like " back it out 1 1/2 turns" only applies to a new carb on a new engine. Worn out old rigs have to be tuned by ear.
Don't even try rejetting mains, air bleeds, emulsion tubes away from factory if you don't have wideband O2 to tune with. Even then, you need the equivalent of one semester's worth of study to "get it". Weber's are tough, I've been doing them for 20 years and still approach each one with caution. BTW, Weber throttle shafts like to wear out in the bores. You'll never be able to tune around them until have the bore reamed oversize, bushed and a fresh shaft installed, by a weber rebuild shop. There's a good outfit in Gilroy CA that are capable and competent.
Oh yeah, 4-4.5 psi, no more. Typical carb pressure regulators usually don't adjust below 5-7, all too high. Get a dedicated weber PR before you even try to start tuning.
i had to run about 3, 3.5 turns out, i figure close counts as long as runs good and the way you like it and nothing is burning up a little rich is better than lean.
78octane, What's the name of that shop?
I used to know a place out west but that's bee loooonng ago.
E
Pierce Manifolds Inc
321 Kishimura Drive
Gilroy, CA 95020
(408) 842-6667