On a 3 HP motor – a 2 or 3 blade prop will not make much difference, but the 3 blade prop will provide a bit more push to plane off the boat, but a 3HP probably won’t plane many boats anyway. The 2-blade will give a bit more top end speed, while the 3 blade will give more consistent speed against a wind . On that model the 2-blade may repel weeds a bit better, they were advertised as weedless props ….but….as I said, with 3 HP, you may not notice any difference. I’d go with a 3-blade on a boat, or sailboat aux power, and a 2-blade on a canoe. I have JW models with both 2 and 3 blade props, and you really have to be looking for a difference – it’s like splitting hairs.
Dave

• This reply was modified 4 years, 9 months ago by outbdnut2.
• This reply was modified 4 years, 9 months ago by outbdnut2.

Well, seeing that you already have several of these with two blade props, you might want to get the three blade to try out. You can always swap em around on the different engines anyway. The thee blade was introduced in 1969 for the 4hp. Early 50s versions of this engine had a three blade also, but I think it had less pitch, this might be an option also….
Like others have said, this exercise is kinda mute on these engines, they don’t have enough power to plane most boats…