Technical Holley 94 3x2 Setup, Boosters Siphoning Gas

Hey guys, as the ***le states there is a major problem going on. The car I am working on has 3 94's on it. All three are siphoning fuel into the crankcase and out of the right side header. I can see fuel on the boosters, throttle plates, inside the intake with plates open, etc. I popped off the air horns and the float levels are correct at 1-11/32" on all 3 on both sides of the float. Minimal fuel in the bowls even though the fuel in the main tank is also at a lower level than I remember from yesterday, which is strange to me since the top of the tank is lower than the inlets to the carbs.

The carbs were rebuilt some time ago, the owner cannot remember when. They were sealed top and bottom before being installed on the manifold. They look brand spanking new, I mean super clean with no battle scars or anything, inside and out. I'm beyond stumped. What's your take on it? Searching didn't turn up much, and I've scrolled through a bunch of threads the last two days.

 

I'm watching this for advice as well. Have 3 94's on an FE and every now and then the centre one floods with fuel and I have to pull the plugs and crank out excess fuel from the cylinders. Done the same as you,float level etc,checked the float for holes. I'm not sure if Dreddy Bear is still on here as he had some great threads on 94's and he helped with my set up. Maybe the threads got wiped when the HAMB changed,

 

Yes it's very unusual, when we broke the engine in on Saturday it ran fantastic, it's all dialed in. I ran it again this past Monday to verify the alternator was working, again no problems. Went to start it Tuesday and it was hydro locked, and a fair amount of fuel came out both headers. The oil is contaminated as well but needed to be changed anyway due to the engine being broken in. I'm at a loss since it just keeps going with no end until the bowls dry out.

 

Blown power valve ?
Does it have vapour coming out of carb when you shut it off ?

 

Deadbeat.
What is FE, ? Flathead engine ?
3 94s too much for flathead ?
Progressive or fixed linkage ?
Possible problems- Incorrect power valves, blown power valves, sticking needle valve.
I'm not an expert, but I have spent about 40 hours reading dreddybears links on 94s.....
And had many problems with my 3x 94s on sbc

 

I feel your pain. Spent most of one summer dialing in mine on my 57 Ford. First off, they don't like more than 3 1/2 pounds of fuel pressure. Next I ended up setting the float level lower than the spec. I also installed 1/2in. spacers under each carb to help keep heat away from them. After I solved the fuel dripping problem I could then work on getting it to run right. As much as I tried, I couldn't get the end carbs to seal well enough to obtain a good idle. I must have tried a hundred bases and all the different tricks to seal the throttle plates. No luck. I finally broke down a bought a couple secondary bases from Vintage Speed. That cured the last of my problems. Been running fine for the last 2 years.

 

I believe these are setting on a hemi, correct Nick?
A lot of good places to start already listed above.
Here are dreddybears links.

http://www.jalopyjournal.com/forum/threads/links-to-holley-94-technical-info.286574/

 

How about a bowl venting issue? Or some sort of an internal air bleed or siphon break that's gotten plugged off somehow? Wrong gasket someplace closing a port that needs to be open?

 

The early 94 has a powervalve that looks just like a modern PV, but it is different. A modern PV and gasket will screw into place but won't seal, fuel will dribble past and leak into the engine below the throttle blades via the vacuum source hole.

 

Look at the air bleeds in the front leg of the nozzle bars. Casting appearance varies, but typically there is a sort of cast pit for each with a very small hole drilled for the actual vent. There are two on each side, one venting the idle p***age and the other venting the main circuit.
I have seen these come out of the cleaning solution blocked even with all else spotless. Few builders seem to know they exist!

 

I had similar problems with the three 94s on the SBC in my roadster. I lowered the fuel pressure and the float level and the problem went away. These old carbs don't seem to like a lot of fuel pressure. The 94s sure ran better than the 97s once I got 'em ironed out.

 

Yes this setup is on a dodge 241 hemi. I ruled out the power valve since the fuel is coming out of the boosters above the throttle plates, and it is slow going. I will check the air bleeds again since Bruce mentioned that on every thread I was able to find, seems likely they all have crud in them if all 6 are dribbling wet. I'll be sure to report my findings, if any.

 

I will add this is happening with the engine off with no fuel pump pressure on a cold engine.

 

Blocked bleeds make that p***age a natural siphon up to the middle of the nozzle bar. With engine off, I don't know how long the bowl could sustain siphoning though!

 

With engine off the fuel is below the boosters, like Bruce commented it won't siphon. Thru the PV is the only path to the engine. If the float is high when you shut engine off it'll wick (siphon) some fuel and you'll see that dampness and vapor rising from the venturi but, it p***es quick (as soon as vacuum equalizes itself) and it won't let any significant amount of fuel into the engine. Again, the only path to the engine is thru the PV. Unless there is a casting flaw.

 

Fuel is always below the path up to discharge, running or not...running, once RPM is up enough to activate venturis fuel is drawn up the nozzle bar to main circuit by the pressure drop in venturi, at idle it is drawn up and over through the other tube to idle holes by low manifold pressure (vacuum). The pathways can work as siphons as long as fuel covers the main jets IF there is no air break in the tube. Those little bleed holes would break the siphon. Main circuit tube ends in middle of nozzle bar and would drip there, idle tube goes around that area and down the other side of bar to the idle and off idle holes.

 

Yes that's what I believe to be happening at this point, the fuel level in the bowls last night was above the jets but low enough that the float wouldn't be able to do its job. My reasoning that the power valves are ok is that I would imagine the bowls would be bone dry by now since the PV are at the lowest point. Once I get them off the engine, each one is getting a tear down. I wish they were strombergs, never had this issue before, but not my car.

 

No additional fuel is being drawn into the bowls either. Trying to think of any other info, I would like this to turn into a really informative thread for anyone else that needs help.

 

Remember that the PV is two inches below the boosters and its pathway if leaking is down to BELOW even the throttles. Jets, which feed main, idle, and off-idle circuits are below fuel until bowl is empty. Only other path towards top of throats would be pump circuit, requiring discharge valve to be actually missing and also discharging mostly below the nozzles-unlikely. You should be able to watch with engine off if those upper routes are wet. If PV were leaking, you would not be able to see the fuel with carb on engine.

Go to this site: http://www.norgv8club.org/all-dcouments-indexed/category/15-service-bulletins
Click on the carburetor section. They have the Ford bulletins on how-it-works and overhaul on both Ford carb and on Stromberg.
The first part contains circuit diagrams that will help you follow the pathways out of the bowl.

 

Thanks Bruce you are quite the knowledgable guy. Yes everything above the plates is WET with fuel. I was looking at the pictures I posted since I'm not home right now, but I think I see one of the bleeds you're talking about right near the accelerator pump nozzle. I'll pop the carb bodies off and pull the crossovers out. If they are clear then we pretty much have a demonically possessed fuel system.

 

Charlie Price @ Vintage Speed has the correct power valves for the older 94's, which I run in my avatar, also, to answer another post, I run 5 lbs. of fuel pressure with no problems.

 

Good to know, I'm at about 4 pounds but this problem is happening on a dead cold engine with no fuel pump action at all. If they end up needing to be rebuilt I'll get a hold of him.

 

Go to this site: http://www.norgv8club.org/all-dcouments-indexed/category/15-service-bulletins [/QUOTE]


Those diagrams are exactly what I needed to see. I'll be printing those up today for present and future reference.

 

Yes I understand your not pressurizing the carbs at this point but 94's should not have a higher than 2-1/2 pounds.

Exceed this and performance and mileage will be affected. This exceeds the design pressure and the needle system will sometimes fail to control this much pressure (the needle is forced off the seat and/or stick). Due to the design of the float system on the Ford 94 (better location of the float fulcrum), it is usually able to control a somewhat higher pressure than the Stromberg.

 

These carbs sat in a shed in Colorado, for who knows how long, and over the office, in the dust for another year, or so.

I would make sure they are good and clean inside.

Are you running a pressure regulator? Where in the system is it, and what is it set to?

Traditional?

 

Also, I built the kickup pretty tall. If the tank is up there, it might be pushing fuel via gravity.

Traditional?

 

There's a regulator by the firewall before the line goes up to the fuel block, I already turned it down to half of what it was at. The carbs are coming off and apart tomorrow.

 

Fuel pressure 1&1/2 to 3 lbs max

 

Hey Clem, sorry for the late reply. My FE series engine is a 390 from a 60's Galaxy. I run progressive linkage and try and keep the pressure down to just under 2. Saying that it has been on there for over 10 years now with many trouble free miles. Just cant remember the PV size atm but I have that written down in my shed,
Cheers

 

Soooo...since our last episode we have had an ignition coil explode due to an internal short in the starter relay "I" terminal, so that means for a decent period of time the coil got battery voltage until the top popped off and blew transformer oil all over the under dash (battery should've been disconnected I know, I know.). So I was dealing with that in addition to the carb issue.

Back the the original task at hand, we have a crankcase full of gasoline, about 2-3 gallons. Nice. Air bleeds for idle and mains are clear of debris. Carbs pulled off, will fill the bowls and see if the power valves are leaking. Probably will rebuild all three since they're on the bench as I type this. So, vintage speed rebuild kits, yay or nay?

I have not told the universe to eat **** yet, but my patience is thinning.