Truck ran great with the old used Eddy 600cfm, i switched to a holley Street avenger 570cfm to try and gain some MPG's. Every since the change I can either get the truck to run & idle great with plenty of power but Diesels when you shut it off -OR- idles like poo with no power but doesnt diesel...I've set the timing and mixture with a vacuum gauge as the timing tape i have i installed backwards and it doesnt do me any good. I'm pulling a CONSTANT 15" at curb idle (850rpm) and 11" in "D" (which idles at 550rpm). The vacuum advance is hooked to ported vacuum which is the same place i had it on the eddy. Idle Mixture screws are set at 1.5 turns out which gives me my best vacuum reading. I've shot both carb cleaner and starting fluid looking for vacuum leaks, no changes. I'm at my wits end, did I just spend $400 on a POS carb?!?!

 

Did you set the float bowl level,it might be too high.

 

What did you set the initial timing at ? Sounds to me like it's retarded too much. The dieseling is from the throttle blades being open to far allowing it to get too much fuel when you kill it. The cause of this is likely retarded timing, which would also result in the poor perfromance when you idle it down to prevent the dieseling.

 

what i dont understand is that it didnt start dieseling until i changed the carb......

 

Can't help you if you don't supply answers to my questions.

 

I don't really know what initial timing was set at, but it ran fine with the other carb. I changed the carb and it wouldn't run so i adjusted so it would run.