On the four row of holes at the WOT end, enlarge only the holes parallel and below (to the rich side) of the double row of holes. I believe the other holes do nothing but drop the pressure inside the spray bar. And enlarge all the others. #80 won't help much, at least that's what I observed. But they helped.
I was enlarging by hand and it took forever so I got a chuck from McMaster to go in an air pencil tool. Then it was a breeze but took a steady hand.
Here's what I ordered from McMaster...
30585A96 3 Each Uncoated Hss Jobbers' Drill Bit, Wire Ga 78,7/8" Oal,0.2" Drill Depth,118 Deg Point
2 30585A95 3 Each Uncoated Hss Jobbers' Drill Bit, Wire Ga 77,7/8" Oal,0.2" Drill Depth,118 Deg Point
1 30585A98 3 Each Uncoated Hss Jobbers' Drill Bit, Wire Ga 80,3/4" Oal,0.1" Drill Depth,118 Deg Point
2 30585A97 3 Each Uncoated Hss Jobbers' Drill Bit, Wire Ga 79,3/4" Oal,0.1" Drill Depth,118 Deg Point
3 30505A5 1 Each Small-hole Drilling Adapter, #99 To #60 Cap, 1/8" Shank Dia, 1-5/16" Oal
Please don't PM me! Email only!
Bob Japundza CFII A&PIA
N9187P PA-24-260B Comanche, flying
N678X F1 Rocket, under const.
N244BJ RV-6 "victim of SNF tornado" 1200+ hrs, rebuilding
N8155F C150 flying
N7925P PA-24-250 Comanche, restoring
Not a thing I own is stock.