I'm thinking out loud here but just for shits and giggles lets try going back down in size on the pilot
jet. Go back to the #35 and if it gets better but still on the rich side go to a 32.5. the main
circuit may not be the issue, it might be the mid range pilot circuit that we have too rich. The 37.5 is based on lower elevation jetting and I'm not sure how much the pilot size fits in with the self compensating features of a CV carb
. The self compensating has more to do with movement of the upper diaphragm and main circuit. The pilot is constant. You may also be able to just turn in on the PMS
to prove my thoughts. Turn it in to about 1/2-3/4 turn total. If it seems better we can go from there.