i have an edelbrock 1406 600 CFM electric choke carb on my 305

i am pretty new to carbs...........
(also i should state that i do not have the instruction manual for this carb)

how do i use the 2 idle mixture screws to set my idle mixture?

also, i believe the car was running a little lean when i had it running last time, because i had a slight backfire when romping on the gas (or the timing could have been too far advanced)

whats the best way to select the proper jet size?

and exactly do the metering rods do?

 

Dont change jets or rods. The standard setup for an edelcrock is 1 and a half turns out on each mixture screw for nearly every setup.
The rods get pulled down when there is high vacuum limiting the amount of fuel going through the jets--------> high vacuum, ------- > low vacuum.

At most you may need a spring set to adjust the flow under different vacuum loads.

 

http://edelbrock.com/automotive/eps_intro.html

 

One and a half turns out is an okay starting point for the idle fuel mix screws and one and a half turns in for the idle speed screw.

Lean when romping the gas could mean you need more accelerator pump shot.

Actual timed 1/4 mile runs is the best way to find the best jet sizes. Start with the secondary jets and look at your trap speed MPH to measure power gains/losses.

The metering rods/primary jet combos allow you some adjustments with your cruise A/F ratios.

For more info you can look here.
http://www.cardomain.com/member_page...217306&page=26

 

so larger rods allow less gas, while thinner ones let in more?


how do i adjust the accelerator pump shot?

 

The arm with 3 holes in the front of the carb. Move down to increase pump shot up to reduce. Yes you have the idea of the rods bigger allow less fuel also lighter springs keep the rods further down in the bore doing the same thing.

 

About halfway down this page:
http://www.cardomain.com/member_page...217306&page=26
explains how to adjust the pump-shot and has some pictures.

 

ok thanx guys

need some more help

i am pretty sure i know the question to my answer i just want to make sure


while setting my timing, i noticed that my engine was idling very high (1500 RPM)

i failed to put 2+2 together, i shut off the engine and adjusted the idle mixture screws all the way in and then backed them out 1.5 turns

BIG MISTAKE

(i am thinking because my idle was set so high, the idle mixture was richened for that reason, so by resetting them, i leaned out the idle mixture way too much)

i then turned my key to shut the engine off because she was pinging pretty badly

engine would not shut off i had everything so screwed up

engine finally shut down about 5 seconds later

seems like it got hot enough to ignite the fuel that was still being sucked in (from my dumbass leaning the mixture out too much)

SO NOW I NEED TO:

set my idle speed screw wayyyyyyyyyyyyyyy down so the engine idles at about 800 RPMS then

that should work happily in unison with the mixture screws being set 1.5 turns out


Am i correct?

 

Yea, you got the basic idea. I'd just check the choke also. Edlecrock set their chokes very tight and sometimes the linkage needs to be bent on the fast idle, the flap could be open but if fast idle is stuck....

 

problem solved thanx for all the help so far

does this sound right?

i have the idle mixture screws 1.5 turns out and i am idling at 850 RPM

sound good?