www.iFourWinns.com

Hi again. Thank you for all the answers!

I've decided to stick with my 140hp engine. But i have a prop question now.

I looked at the four winns homepage at the 1990 180 horizon and saw the prop dimensions on the outboard engines...
120hp 13x19
150hp 14½x19

On my 140hp i have a 15½x15....to me it sounds like i should have something between the 120hp and the 150hp prop size...

Do you guys agree? What would be the difference if i changed to a 14½x19? I'm really don't know anything about props!

/Johan

What are your RPMs at full throttle?

A 15" pitch is way too low for that boat. I'd guess you are over revving without achieving more speed.

I wouldn't want to rev that motor much over 5200 rpms

You will reduce your revs by about 200 rpms for each pitch you increase the prop pitch.

So, if you are reving at say 5800 rpm at full throttle you will want to increase your prop pitch by 3 inches to reduce it 600 rpm. So that would be an 18" pitch prop...very uncommon...but the example still holds true.

I would suggest getting a 19" pitch prop. That will reduce your WOT RPMs by about 800.

The key is to get the WOT RPMs very close to the max for the motor....that will give you the best performance.

_________________
Current Operational Boats:
'04-Four Winns 180 Freedom 150 HP Evinrude
'72-Chris Craft Commander 31 Sedan Twin-350Qs

I have an 89 200 Horizon with a 175 Johnson. I guess they didn't make many as i have yet to see another one.