Holley 600 Street Warrior Fouling Spark Plugs

[1985K5Blazer305]

Hello, a friend of mine gave me a relatively new Street Warrior that had been collecting dust in a shed for some years and needed a rebuild. Cleaned, rebuilt, and installed, the Holley was dumping fuel from the primaries. 350 sbc wouldn't idle and was running on 6, headers for cylinders 1 & 2 were cold and the plugs were wet and dripping in fuel. At "idle," fuel was showering out of the primaries and from what I understand you shouldn't see liquid fuel pouring out as it should be atomized. To preface, this motor ran smoothly on a quadrajunk prior and has new distributor, plugs, and wires, all of which are confirmed to be sparking.

First thought was to check float heights. With the sight hole removed, turned the needle & seat until fuel just barely started to leak out of the hole. No luck. Initially set the floats to be parallel with the bowl when inverted.
Next, stuck/not sealing needle? With the primary bowl removed, the needle moves without restriction and falls back down under its own weight. To check sealing with the seat, I blew air through the bowl inlet and lightly closed the needle with my finger, and no air got past the needle.
Pump providing excessive pressure? With the quadrajunk still on, I tested the pump and saw consistent 5-6 psi at idle and rpm.
Bad power valve? The valve that came with the Holley had a lot of play and looseness to it. With this power valve the primaries were showering fuel at idle. So I installed a new power valve and now the primaries drip at idle and shower at rpm (see video).
I've played with the air/fuel mixture screws within the ranges 0.75-2.5 turns out but no avail. I will mention that the car would not start with the screws fully in. Any carb tips are appreciated as this is my first rebuild. The carb is just running extremely rich, fouling plugs, and smoking out the tailpipes. Not sure what else there is to touch or adjust?

Specs: 80457-3 Holley, 64 jets, 110 needle and seat

Showering Primaries Video Link:

Thanks in Advance

 

[Bent77]

I’ve seen this occur after a rebuild when the wrong metering plate gasket got installed. Otherwise I think you have something in it still

What was wrong with the Qjet?

 

[1985K5Blazer305]

I’ve seen this occur after a rebuild when the wrong metering plate gasket got installed. Otherwise I think you have something in it still

What was wrong with the Qjet?

I'll double check my gasket, I matched the new one before scraping off the old one and made sure no holes were blocked but I'll double check.

The Qjet ran well except that at anything above 2800ish rpm, I'd experience power loss, no acceleration force, and exhaust burbles. Initially I thought a floating valve or timing issue, hence new distributor, but I wanted to consider a fuel issue before getting into the heads. Potentially that at rpm the fuel bowl was draining at a faster rate than it was filling. Cleaned the fuel tank, new sending unit, blew out the fuel lines including vent, and tested the pump. Everything up to the carb was working properly and instead of putting time into the Qjet I decided to consider a more performance option.

 

[Bent77]

Well, a proper tuned Qjet will do everything that Holley will. Sounds like you had an issue on the secondary side, like opening too fast or a rod dropped down into the jet

 

[shady]

Id almost lean towards timing maybe
Sounds like you covered the carb bases .. but I've never been very carb smart lol.

 

[1985K5Blazer305]

Update, although I matched the metering plate gasket with the one that came off, I tried the other version (one without the cutout around the accelerator pump port), and the condition has improved. The cutout in the gasket left an air gap between the ports and was dumping fuel into the power valve chamber, now it seals properly.

There is no liquid fuel dripping from the boosters at idle; fuel is only visible when accelerating which I believe is normal. The carb still runs rich and fouls plugs 1 & 2 in 2-3 minutes instead of 2-3 seconds. I'll dial in the idle mixture screws but outside of this adjustment, is there anyway to further lean out the carb (aside from smaller jets)?

 

[Bent77]

Jets
Idle screws
Power valve (make sure the rating matches the vacuum)

What is your idle timing set at with the vacuum disconnected and also connected?

 

[1985K5Blazer305]

I'll double check the power valve rating. Timing with vacuum advance disconnected is 10 deg BTDC, I don't remember what it is with it connected, although I know the rpm picks up so I have vacuum advance at idle, I'll get a number tomorrow. I appreciate the help Bent77.

 

[Bent77]

No worries

Take a note pad, wrote details down, wrote down what you change. You will get around on it

Double check the firing order

 

[imiceman44]

I would still go back to the qjet, and work on the adjustments.
Unless it's a street car that is going to race, I never saw a benefit from any other carb.

 

[Fastereddie]

Dump the holley