Valiant 470 sport and mercury 40hp efi

[jannem]

Hi all,

I think my engine has too small prop. It takes the max rpm so fast even if i have 5 person on board. The max rpm is now about 6200rpm which feels way too much. The speed is with max rpm only 23knots. What kind of prop u guys think i would need to fix this?

[two stroke mick]

You will need to give details about the engine for a reply to be made.

[jannem]

Originally Posted by two stroke mick

You will need to give details about the engine for a reply to be made.

Mercury FourStroke 40 EFI 3-cyl. model 2012

[matt h]

and your current prop size.??? it really is a trial and error job.but as a pure guess something like a 10.5x14 ish

[jannem]

this is all the information of the current prop that i can find

[jannem]

What about the top speed, am I just dreaming to get over 30knots with this combination?

[jannem]

Okay so the pitch of the propeller was 11 and tested 14 one week ago snd it was too big cause the top rpm went under 5000. Now got the P13 propeller and will test it on saturday so we will see how it works!