Oversized 4blade prop equals poor performance. Questions

803803 Posts: 175 Officer
I have a 17ft flats boat pushed by a (2006) 90 2stroke Yamaha. The previous owner put a large PowerTech 4 blade 15 pitch stainless prop. Cruising it burns very little gas at around 3500 rpms (30 mph) but only gets to about 35 mph at 4800 rpms. Boat is also very sluggish in acceleration. It accelerates to around 3000 rpms and slowly gets on plane then the rpms will jump up. I am assuming this is related to the prop though 4 blades should get on plane easier.

Any advice on how to get a little better optimal rpm and acceleration performance. I am very inexperienced with dealing with prop dimensions.
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