carb. guru needed

[camd64]

so here is my problem, my carb. (1406 edelbrock) runs really rich at idle and just off idle. I have checked all the stuff I can think of and can't seem to figure the problem out. I have the insulator gasket, the choke turns off when it is warm, fuel lines are away from heat, fuel pressure at 6psi, and i am 1-1/2 turns out on the mixture screws. what am i missing? I tuned the idle with a vacuum gauge then after test driving it felt lean so i stepped up one rod size to the 73/42 and a size down on the spring to a 4'' (yellow). that seems to help a bit with the lean kinda stumble off the line but now I wonder if the rods have anything to do with the idle circuit? any carb. guys got any ideas?

 

[green1]

what is your vacuum?

 

[demon sizzler]

Metering rods have no effect on the idle circuits; you could remove the metering rods completely and it would not change the idle. So, if you had to adjust the idle speed a lot to get an idle, you have too much idle circuit and will have to advance the initial timing and back off the idle speed accordingly. One other possibility exists; you could have a sticking float needle which will cause both the idle circuit and the cruse circuit to be rich.

 

[camd64]

I have about 17 inches at idle.

 

[camd64]

demon sizzler, i pulled the top off and checked the float setting as I heard eddys often are off but mine where right at 7/16 and drop at 15/16, i even checked the needle and seats and the floats for any leaks. also my timing is set to 14 initial so I will try 16 and see if that helps. thanks.

 

[demon sizzler]

Have you observed any vapor in either primary bore after you shut off the engine? If so, you are over filling the bowl(s)and may have a worn float needle causing the carb to run over rich.

 

[camd64]

i haven't noticed any. when i pulled the top off though i made a point to check the level of the fuel in the carb. and it looked the same on both sides. i looked down the throat when it was running and didn't see any dribbling fuel or anything either. only thing i have seen is a couple stains on the outside of the body but i think thats just the top gasket weeping a little.

 

[cudavert]

With the correct idle speed, can you turn the idle mixture screws in and eventually make the car stall?.......how does it run with the screws only 1/2 turn out? Not trying to show any disrespect, but are you positive that it's rich? Because you mentioned that it's rich @ idle and just off idle, yet it's got a lean stumble which you tried to correct......

 

[camd64]

yeah you can smell it and see it puffing a bit. plus you can feel it lugging until you open it up enough or wide open the throttle. then it will clean right up and pull good. and yes if i run the screws in it will stall out.

 

[matthon]

I recently went through carb issues myself, it smelled like it was running way too rich, and I began checking/replacing things.
Once I put high octane gas in, the problems stopped.