RE: best carb or mod for ryobi 31cc. need more power
wt526 carb has 7.94 mm venturi would look for replacement carb in 9-11 mm range.
FWIW: Walbro 167-A is 11.11 mm
Have you made any adjustment to reed stop to allow reed to open further? I adjusted mine to allow 1/8" allen wrench to slip between stop and reed.