ORIGINAL: karolh
Try a 20x8 or 20x10.
Karol
Perhaps you've only used Zenoahs !
MVVS are a high performance engine.
Those props are way too small. My MVVS 35 turns a Menz 20 x 8 at 7000, so you'll need at least a 22 x 8 or even larger for the 45, which is a real powerhouse.
Great engines