Holley Carb tuning

[bill paynter]

I was wondering
when adjusting the air fuel needles on the sides of your carb. sorry I don't know the accurate term, how many turns do most carbs require.
the reason I ask, most motors that I have tinkered with usually are set around 1 to 1.5 turns, but my new 600 holley on a 273cid won't run right with less than 2 turns. do I need bigger pimary jets??? currnetly I'm using 62's in primary's

 

[redfastback]

the amount of turns is AVERAGE. if you have a vacuum gauge or a tach, set them to the highest vacuum /rpm reading and then about 1/4 turn back in to take the rich edge off without dropping the reading. 62 jets may be a little lean but maybe not, do some WOT runs and pull some plugs. they will talk to you.

 

[2shelbys]

This is a little trick I use to set them correctly. After the engine is warmed up a little, drop the idle to where you want it. If it tries to die don't hit the throttle, lightly tap the accelerator pump arm. If it gets better you are too lean, turn the screws 1/8 of a turn out. If it gets worse you are too rich, turn them 1/8 of a turn in. Repeat until it is happy at the target RPM.

 

[dusterdon]

The primary jets aren't in use during idling. Just adjust the needles to where you get an idle quality that you like.

 

[bill paynter]

thanks guys, I'll give it a try

 

[dgc333]

62 jets may be a little lean but maybe not, do some WOT runs and pull some plugs. they will talk to you.

FWIW, 64's are the stock size in a 600 Holley so 62's aren't out of line.

 

[redfastback]

yep, 62's might be just right. only driving will tell.