Need some help from the HAMB wisdom. I have carburetors where fuel flow is intermittent from the boosters. I’m not a carburetor expert at all but trying to help a friend. He has a 383 SBC with a dual quad Tunnel ram that won’t run well. Ignition is spot on and everything is new and working fine. I’ve checked fuel pressure, float levels and it idles pretty good. The problem is that when you open the throttle sometimes fuel pours out the boosters and sometimes no fuel comes out. I’ve never seen one this inconsistent. About 50% of the time there is no fuel.
Do you have a fuel pressure gauge so you can see what the fuel pressure is doing ? Also helps to know what carbs, edelbrocks don't like more than 5, holley will handle a little more. Also what kind of fuel pump ? Mechanical or electric and it's specs... ...
Awe have a fuel pressure gauge and it is steady at 8psi and drops to 7 at wide open. It’s a Holley electric pump. I don’t know the carb numbers but they are Holleys
I agree, we need a different regulator however, And I don’t think that too much fuel pressure would cause no fuel in the carburetors
Those look like 4224 center squirters, 660 CFM. You mentioned sometimes not seeing fuel from “the boosters”, are you referring to the accelerator pump nozzles or the venturi boosters? The nozzles should give a shot of fuel as soon as you move the throttle. The boosters will show flow as rpm climbs and the venturi action pulls fuel from the float bowls.
Check that gauge to see reading correct. Not to many small ones read correct in last 20 yrs. 5-6 psi is enough from known good accurate gauge . you say some times fuel leaks some time then Not , sounds like talking about Squirter. yellow circle's check accelerator pump cam adjustment No play will push fuel out of squirter's. About .040 -- .070 gap needed . & Bad float Needle seats can not move freely & stick most time will cause flooding
The squirters and accelerator pumps are adjusted correctly, I spent the afternoon adjusting the accelerator pump linkages and swapping pump cams trying to get rid of an intermittent bog. once I got the squirters working properly I noticed that about half the time fuel isn’t coming out of the boosters. After staying up late reading, I’m concerned that the combination of the tunnel ram and the camshaft are causing not enough air flow to pull fuel from the boosters.
I see Stalh pattern headers More spec on engine . Vac # @ idle Idle RPM's Plugs Converter or stick . Compression What Fuel grade # using Octane matters to how tune engine where the timing set 15-20 btdc , some need more @ base . What's the Total . Fuel out of booster's when ? @ Idle Or After transfer slot into cruise & WOT . No fuel should come out booster's @ Idle . Carbs are they stock from box or have been changed around beside cam squirters . Are the carbs center squirter's. Have you looked to see where ****erflies are set in relation to transfer slot's ? Disconnect the secondary , Go from there try to help diagnose issue & where to start changing .
Stock 4224 carbs are designed for Tunnel rams. Float Level, needle and seats. Sticky needles... can cause. These are very responsive carbs.
IMHO, 4224 carbs were designed for wide open throttle performance and not for part throttle response. The were designed for manual transmission, low gears, and lots of flow (heads and cam). If that doesn't describe your friend's car, I'd advise swapping to vacuum secondary carbs.
It’s in a nostalgia drag car with 5.13 gears and a power glide with a loose converter and a manual valvebody so it should be ok for the purpose. It’s jut not giving fuel consistently.
Loose converter 4k 5k Is there 2 step or throttle stop ? off ****on should be p*** idle circuit & cam shot . Have you verified fuel psi & delivery is there alot of br*** fittings , Mention again the gauge shown notbto many are good & accurate .. Where the fuel tank Front Or rear type fuel pump Just to Mention fan Not recommended over 6 k rpms
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