Stalls when I let off

[mikewitt]

Hello Fellas...

Since my V8 with 94 carb was running real rich, after the carb rebuild. The Forum got me switching out the Power Valve. And it did leak on me after I filled to bowl.
The new PV doesn't leak, but now I can seem to set the fuel mixture for idle and idle screw. If I get it set curbside, drive, when I got to stop, RPMs drop off and it dies. Couple pumps of throttle... can drive again... or 2nd gear coast to get-er started again. But dies at next stop.

If I set idle way high, it won't die, but that just ain't right.

What ya think? Vacuum leak.

 

[mikewitt]

Sorry for the typo....

The new Power Valve did not leak. So some improvement on running too rich.
Problem now is the rpms fall off too much when coming to a stop, and motor dies.

Am I too lean on my idle mixture ?

Thanks

 

[ford38v8]

Sorry for the typo....

The new Power Valve did not leak. So some improvement on running too rich.
Problem now is the rpms fall off too much when coming to a stop, and motor dies.

Am I too lean on my idle mixture ?

Thanks

That sounds right. While keeping the idle adjusted to 500 rpm, open one mix screw to the point that further opening doesn't increase rpm. Then do the same to the other mix screw. If you have a vacuum gauge, it should increase vacuum and steady out, indicating an efficient idle. One more thing, the engine should be at full operating temperature before attempting this adjustment.

 

[TerryOH]

The initial adjustment for a single 94 is about 3/4 of one turn out from all the way in (by hand). If your final adjustment is over one turn out on either screw or less than 1/2 turn out, you have a problem with the idle circuit. Suggest you put a vacuum gauge on the engine it will tell you a lot. Your looking for 18 to 21" of rock steady vacuum at idle. It is a good idea to make sure both carb surfaces are flat before installing the PV chamber gasket and the screws.