ive been looking at a new carb for my truck, and was wondering how the four corner carb setup works, how do i jet them? how do i set the idle mix?

 

What brand? Holley, Demon?

 

Demon, though i think that demon uses all holley parts, power valves, gaskets, jets, accelerator pumps etc.

i only have enoughjets to have two in at a time, so i was wondering if i could find which jet size i need using just the primaries then when i find out, order the size jets i need.

or do the secondaries take a different jet size than the primaries?

 

Four corner idle adjusts very much like any other one. I've done it but it's been a very long time ago and I can't remember the specifics but it was not too hard. I usually ran one or two sizes bigger jets in the rear, jets are the same. New carbs usually come jetted pretty close to optimum, often just a little rich.

 

The four corner idle shouldn't change jetting at all, I have road demon 625 and I just screwed them all the way in and then out one turn as a starting point the only hard part was trying to remember which ones you had turned and which ones you hadn't, mine wound up idling great at about 800-850rpms with the rear just about 1/4 turn richer, and that with decent sized cam and a single plane intake.
-Johnboy

 

You can hook up a vacume guage and adjust the 4 corners for the highest vacume. Once you get your idle circuit set, you can select your jets. I like to do it by reading the plugs.