Maybe the idle circuits have changed, but rule of thumb on idle mixture screws for a Holley were start at 3/4 turn out, then adjust from there. Spent decades starting there and had much success. (yes, did it for a living 40+ yrs)
If you adjust the idle screw don’t forget to go back and check the accelerator pump as changing the idle screw will affect the tightness if looseness of the accelerator pump linkage.
If it's coming out the vent tube either your floats are adjusted way too high, your needle is stuck open (first thing I do when I see an overflow is smack the float bowl with the back of a screwdriver. Will usually free up a stuck open needle) or your fuel pressure is too high. If it's coming out the float adjustment screw you either don't have it tight enough or your gaskets are bad.
Thank you for answering buddy I greatly appreciate it is coming out of the tube that's sticks out of top of carburetor....the front is primary an back is secondary right? It's hard for me to explain like this lol.. I've taken both of the check valves out an they seem ok... it's my dad's 64 Impala I will try what u have mentioned an will get back with you thanks
Maybe the idle circuits have changed, but rule of thumb on idle mixture screws for a Holley were start at 3/4 turn out, then adjust from there. Spent decades starting there and had much success.
(yes, did it for a living 40+ yrs)
If you adjust the idle screw don’t forget to go back and check the accelerator pump as changing the idle screw will affect the tightness if looseness of the accelerator pump linkage.
That would be the air fuel mixture screws first
Technically Holley refers to them as Idle Mixture screws.
@@KPracing412idle mixture. There’s also an idle screw. And what you called the “idle” screw is the idle mixture
Awesome video. Do you have a video on your vacuum hose routing for this carb?
Very cool.
💯 good info...
Great info, thank you!
Thanks Hoss
The best way to adjust any carb is with a vacuum gauge, you want it to idle consistently and as lean as possible with as much vacuum as possible.
Finally someone who understands peak of lean, and that running an engine lean only hurts it if it's designed to run rich.
the lean drop
Be Sure to Obtain Holley Carb Manual. You'll wear the pages out before carb runs to your satisfaction !
Dont know much about carburator but I'm trying to gwt my dad's old el Camino going it sat for a long time n the carburator is running super rich.
Actually, you should adjust the fuel bowl levels before you do anything.
Hot rods and dad bods 😂
Why would fuel be coming out the top of carburetor I'm in process of adjusting they primary an second dary a Holley 600 please help me lol
If it's coming out the vent tube either your floats are adjusted way too high, your needle is stuck open (first thing I do when I see an overflow is smack the float bowl with the back of a screwdriver. Will usually free up a stuck open needle) or your fuel pressure is too high. If it's coming out the float adjustment screw you either don't have it tight enough or your gaskets are bad.
Thank you for answering buddy I greatly appreciate it is coming out of the tube that's sticks out of top of carburetor....the front is primary an back is secondary right? It's hard for me to explain like this lol.. I've taken both of the check valves out an they seem ok... it's my dad's 64 Impala I will try what u have mentioned an will get back with you thanks
What model is that
That's a Holley 4150 750cfm. It has the choke horn milled off.
@@KPracing412i just went and twisted each screw the same in each side and my mechanic need his ass cut