Holley Carburetor Troubles

I just bolted on a Holley 600cfm Carb on My '66 Ford PU and I started it and gas started pouring out of the vent tube. I'm not really experienced too much with carburetor's and well whats causing this and what do I do to fix it?

 

sounds like something in the needle and seat....( that screw head with the nut under it....on the front bowl...) pretty common brandon

 

Junk in the needle and seat or the floats are set to high. Is the carb new, used or rebuilt ?

 

Go to the LPS and get some of those plastic see through float bowl plugs. It makes setting the float level easier if it's too high to start with (Don't leave them in though, they get squishy and start leaking after a few months). While you are there, get the little red Holly carb book, you're gonna need it..... It's a must for tunning them. I also recommend the Teflon seats if you have a hot running engine. At least I'm ***uming they are still made. I haven't raced in 12 yrs.
FYI, try backing off the flathead screw 1/4 turn first and turn the nut out a couple turns (that should cause the seat to drop). Don't over tighten the flathead screw when you tighten it back, I always used a stubby screwdriver. See what happens.

Just in case (please don't get mad if you know this) the float plugs are p***engers and drivers side of the front float bowl, 1/2 way up, usually a flathead screwdriver is needed.

 

sounds like a float level problem, take out the br*** plugs and adjust by turning the screw until the gas is at the very bottom of the hole and then screw the plug back in....if its not that, it could be the needle and seat and, its actually a very good chance it is if the carb was used. Holleys are great carbs. Ive used them for many years and they perform great. I wont use another car in a single carb or dual quad configuration (personally) by the way, those "teflon seats" mentioned above are still available and are highly recommended. Good luck!

 

Thanks ya'll, tomorrow morning I'm going to try adjusting the floats. Its my first time to ''really'' start adjusting and tuning carbs. I mean I've tinkered mainly setting idle ,but never really done anything serious. So all the help is appreciated right down to the simple stuff.
It is a used carburetor I got it from a guy who says its rebuilt but as far as I'm concerned its a very clean used piece. Thanks again

 

Keep in mind that certain new Holleys do not have adjustable float levels, so in that case it's generally debris in the seat, or excessive fuel pressure. It depends on the particular new Holley model in question as to whether they are adjustable or not. Most new models are still adjustable.