Again with the lack of knowledge I have with carburetors... what would I gain from that?
It provides more fuel in the primary circuit. It helps out with the length of time needed for the enricher to stay on, and, in those instances where the PMS
is adjusted 3 1/2 out or more, the larger pilot
allows for the PMS to be screwed in further to something between 2 1/2 and 3 turns out. When the PMS is screwed out to far, they sometimes vibrate out.
The 37.5, is a nice small step. Several on the forum are running 40's.