225 2 stroke to F225 Prop size and pitch same?

[magnoman]

I am going from a sws 225 2 stroke to a F225 four stroke. was wondering if the prop from the 2 stroke is the same size dio and would the pitch be the same. I was running a aluminum on the 2 stroke getting about 5500 max rpm.
I think it was 15x17 ?
Thinking of going with a SS for the 4 stroker any suggestions?

 

[yamamarinetech40]

Re: 225 2 stroke to F225 Prop size and pitch same?

ok, nobody can answer that question, really....what's the boat? If you were only getting 5500 from a healthy 225 2stroke with a 15x17 prop you are pushing either a heavy boat or shaped like a barn door....was it a four blade?

The other thing to remember is that when you go to stainless you would normally DROP 2" in pitch...that would put you at 15X15 which is a crazy prop....and also you want the F225 to get up around 6000, not 5500.

 

[magnoman]

Re: 225 2 stroke to F225 Prop size and pitch same?

It is a 22.8 winner WA cuddy about 3500 lbs w/o motor. Motoris on a bracket full transom.May be it did get up to around 5700, but it had a good hole shot.I never ran it at wo throttle it cruised well at 4200rpm. I did try a SS this summer with the same 15x17 and there was no bite and higher rpm around 6k. I did not know you have to go down 2" with SS?

 

[JB]

Re: 225 2 stroke to F225 Prop size and pitch same?

I think this discussion belongs in the Prop Forum.

Going there.

 

[magnoman]

Re: 225 2 stroke to F225 Prop size and pitch same?

Your right!

 

[gss036]

Re: 225 2 stroke to F225 Prop size and pitch same?

I switched my Merc 200 hp over a couple years ago to a SS prop of the same size and really didn't notice anything other than the SS 14 1/2X17 has a little more cup to it and it really held good on turns and I was able to trim out a little more w/o breaking loose. I think I might have gained a little bit on speed by being able to trim out more. Definately a lot more weight there.
The inside of the exhaust was different shape and it changed the sound of the exhaust a little, so had to get used to the sound.

 

[rodbolt]

Re: 225 2 stroke to F225 Prop size and pitch same?

yamaha reccomends the 61A prop hub as its stronger than the older 2.6L stuff, if its already got the 61A hub then also make sure the thrust hub has a small groove machined on the OD indicating its the high thrust model.
most ss props are cupped while most Al props are not, cupping reacts almost like changing pitch, its also why usually,not always, when your switching from Al to SS you drop a pitch size.
best advbice I can give ya is simply try it and see, but you do need to turn about 6Kwith a normal load, use of a vented prop will help hole shot.