|
I think those are called transition ports so that the air above and below the butterfly valve equalize smoothly and thus when the engine moves off of idle it doesn;t suddenly surge.
Carbs used to have these.
Roguh idle can often be traced to bad wires and air leaks. Have you tried cleaning your idle control valve?
Haasman
__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)
|