I got a new Nepallo 20 with a 90HP Suzuki, but I'm dealing with some prop ventilation. At neutral trim, it vents at full throttle, and with a full load, it happens at various throttle levels. Dealer swapped the 3x13.5x15 prop for a 3x14x13, which helped a bit but it still vents at full power. Any simple fix for this? Dealer hasn't been much help so far