change over valve
 

The later 930's use a change-over valve between the throttle body and the retard on the dizzy. I just obtained a new one and want to be sure I set it up correctly. It is part # OEM- 91161812300. On the part there are 3 ports. Displayed on the side of the part there is a 1, 2, and 3. Well, without any info on 1, 2, and 3 I can't be sure which is which. The way I have it set up is...
1. to throttle plate port
2. to atmosphere
3. to dizzy retard

Anyone know if this is correct?

Emission related?