Holley Choke Problem

Holley 470 Truck Avenger on a Buick 300. The Holley ran okay 10 months ago when I pulled it off the :v6:. Swapped in a Buick 300 and now having some choke issues. Or it could be that the choke was bad but temps were warm enough for me not to notice last time it was driven.

Basically loading up on fuel at idle. When the engine first fires (cold) and I let the choke do its own thing, the choke plate stays mostly closed and I can shine a flashlight in the crack and see fuel spraying UPWARDS out of the squirters and splashing onto the bottom of the choke plate. The fuel is so bad that I am fouling plugs to the point they don't fire, my eyes burn from raw gas in the exhaust, I actually had to pull a couple plugs just to scrape the soot off to get them to fire again. This is only at idle, if I rev it, the fuel clears out and the engine runs like a raped ape. When I inspect the choke plate, the bottom is soaked in fuel.

I have never seen this much gas come out of the squirters at idle, and not sure why it is spraying UPWARDS. I have adjusted the choke to open earlier, but there is still some time when the engine is first cold that it is just fouling the heck out of the plugs. Any suggestions appreciated.

 

How does it run when it warms up? Almost sounds like crud in the float needle and seat allowing too much fuel in. Common when a carb sits for a while.
If it runs ok when warm try adjusting the choke plate open a touch more when cold. Possible not enough airflow with the choke plate closed and causing what you're describing.

 

The choke should be fully closed when cold. I usually like them to lightly snap back when tapped with your finger. Once the engine starts, the choke pull off should open the plates approximately 3/16". If the pull off is bad or out of adjustment, the engine will run rich till the choke heats up and opens.

 

When you say "squirters" are you referring to the accelerator pump squirters, or the main boosters in the center of the venturi bore?

 

I couldn't tell if it was accel pump or venturi, but the fuel was accumulating on top of the screw that holds the accel pump squirters down and even a few drops squirting up past the choke plate.

Made progress today. Pulled the HEEP out into the drive so that I wouldn't asphyxiate myself while it was running, then pulled the choke. I found that the bimetallic strip was not even connected to the tang. The bimetallic was probably only pushing the the choke along a little as it expanded, rather than pulling it. Not sure how this happened. I don't ever remember taking this choke apart before. It is opening up quite a ways now, and not flooding at idle. Now I have to take it apart again on account of I bumped up the high idle while I was in there and now it is a little too high, but minor problem compared to where I was at. Thanks for the replies.

 

So I got the choke set correctly, and I had a really good quality idle and thought I was done with the problem. Wrong. So the next thing that happened is I had no transition circuit. It idled perfectly, but as soon as I would give it any throttle whatsoever, it would die. After some tinkering, I decided I would adjust the secondary throttle stops. Problem is, you have to remove the carb, flip it over, make a guess at your adjustment, put it back on the manifold, hook all the lines back up, start it up and find your adjustment was wrong, then repeat the process. I am about 1 more wrong guess away from ordering a fuel injection kit. Anyone have a good advice on getting the transition circuit properly tuned? I've Googled and read a lot of internet theory on it, and to be honest I don't trust a lot of it. So far I have ended up with either no transition if the secondary throttle stops are almost completely closed, or it seems like a make the tiniest of adjustments and I end up with a 1500 - 2000 rpm slightly rich idle. Can't seem to get inbetween.

EDIT - The rich fuel is due to a drip out of the secondary venturis at idle. Not sure why. If I blip the throttle, it will go away for a while, but then come back. It is about a one drip per second rate. It is not atomizing because the plates are almost completely closed. Every time the drip finds its way to the manifold, I get a little stumble from rich mixture. I cranked down on the secondary float a little, and it did seem to go away, but my fuel level is too low now.

 

Run some ChemTool through it, or SeaFoam. To clean or clear the circuits.
If you put that carb on the 300 and the carb has been sitting unused it may have varnish plugging up the little passages.

 

You need to fix that fuel dripping off the venturi before anything else. Bad/dirty needle & seat? Bad float? Too much fuel pressure? Take care of that problem & then see where you are.

 

I got the drip to stop. Pretty sure it is float adjustment, not bad float. I blew all the passages out with aerosol carb and choke cleaner prior to installing. I think it is just a matter of adjustment, but the adjustments are compounding each other. This secondary adjustment really has me irritated right now. I'm talking about an almost imperceptible amount of movement of the secondary throttle plates against the stop seems to make the difference between no transition and part throttle idle. Finding the correct adjustment is proving difficult.

 

Made good progress today. FWIW, if you need to reset your Truck Avenger secondary throttle stop, I recommend bringing the stop up until it barely touches the bottom of the secondary plunger linkage, then going .020" more, right around a half turn of the set screw. It's hard to make an exact adjustment; you sorta have to just put the feeler guage next to it and take a swag, repeat until the results are satisfactory.

 

Are you running the original power valve? The TA470 comes with a 25 power valve, which is very low. This could be the source of your off idle transition problems. For most applications a 44 to 65 power valve works better, but this is entirely dependent on how much vacuum your engine produces.

Edit-sorry, meant to say 45 to 65

 

6.5