i just replaced my 2 barrel with a holley 600 vacuum secondary carburator yesterday and i've been having some problems with it at upper RPM's, its a 4150, used for a short period of time, no mods done to it

i dont know jack crap about holleys, so it could be somethin simple, but past 3500rpm it either bogs like its starving for gas or it missfires like its gettin too much gas, and sometimes it goes smooth until i ease off the gas and you can feel it sputter a little until the RPM's go bad down past 3500

any idea what would make it run like this at upper RPM's?

 

Did you rebuild this carb before install? And did you add a high performance fuel pump?

 

Sounds like you are running out of fuel. Check your fuel pump like Z28SORR mentioned. Also check the jets, you may have to increase your secondary jet size some.

 

Check the fuel level in the rear float bowl. If it is too low, you will go lean when secondaries open.

There is a brass sight plug on each of the float bowls on the passenger side. Remove while engine is running, car on a level surface. Level should be just at the bottom of the threads, dibbling out. You adjust it by putting a 5/8 wrench on the needle nut, then loosen the lock screw. Counterclockwise to raise. Then lock it down quickly (fuel will squirt out) and see what effect it has on level. 1/8 to 1/4 turn at a time.

Since you had to change the intake, is there a possibility you timing could be off?

BTW, one of the neat things about Holleys is that if you get a piece of trash in an inlet needle, you can just pull needle out the top, clean it, and pop it back in. You will know if there is trash in a needle by the river of fuel running out when you remove the sight plug.

BTW #2, never install those clear plastic sight plugs. I've seen guys seriously misadjust fuel level due to distortion caused by clear plugs.

 

i didnt rebuild the carb before installing it, i did replace the accelerator pump because it was leaking, i put in the stock 30 cc pump, the only other accelerator pump i know of is the 50cc pump that requires a spacer so it wont hit the intake, is this the high performance pump your talkin about?

i did check my fuel adjustments like what angel said and my rear float was way too low, and my front float was way too high, also my idle mixture screws were 1/2 turn out

it runs a lot better now, pulls real good and its smooth in the upper rpm's, it still spudders when i stomp the gas though and smooths out immediately, as if theres a problem with the accel. pump, but it also still spudders a little when i ease up off the gas slowly

thanks for the responces, i've raced with a 2 barrel for 4 years because i dreaded the day when i had to learn to adjust a holley

 

4 years on a 2 barrel? thats not even living man!!!