Foamcut, I have a 28cc mac that I used a 24# carb on the 27,28# carb would not transition and gave me the same top numbers as the 24 carb did, I just trying to say don't get to hung up on the 11 mm carbs everyone talks about some engines can't handle it. I used the stock carb to get running and to check my glow fuel mix then just went up sizes in carbs till I found the one that ran best.


FWIW my mac spins a 18x6 @7400 on gas/glow