king of shaves trouble with prop

[ahbeating79]

I have a king of shaves mono 31 running on 12 cells with stock motor and using a stock spartan prop which its well I get 30 to 32 MPH I tired a 3blade 38mm prop and a 40 mm prop a 2 blade and can't get up on a plane at all only with the 42 mm spartan prop I get on plane no problem no over heating every thing stay cool need other prop ideas needed please

[jamespl]

Just cos it's 40-42mm doesn't mean the pitch is the same. I got a 40mm prop from HK and my kos was rubbish. Try an x640 or x642 and watch it go. Beautiful looking boat but it handles like a trud plus the hull is so thin it's unreal.