www.iFourWinns.com

Greetings from Finland. Boating season is starting here in Northern Europe. I'm looking for new prop for my 1989 Sundowner 225 5,8 litre with OMC Cobra. I have a Solas 14 1/4 x 15 stainless in the boat and it felt last summer that I'm not reaching top speed of the boat. I've read some writings here at the forum and yes...I should check the speed with GPS and measure engine RPM with proper instrument. The problem is that the boat will be taken to our lake next weekend..so now is the time to change the prop if needed...

Does anybody know what is the original prop for this boat? I think it is aluminum 15X17 or could it be 14,5x19?? Any experience which one works? There is a few local companys that sales for example Solas or Michigan props here...like this one..

http://www.uspartsmarine.fi/potkurit/omc?cat=859

The most important thing is that the engine reaches its specified max rpm. Your top speed will be a function of power, weight/load, trim angle etc. get the rpm
right the top speed is not that important. If your rpms are too it will strain the engine and cause engine damage ( cyl head overheating, burned/tuliped valves etc).
Only way to tell is experiment.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Thanks for your response...I agree with your thoughts. I have a feeling that the engine is running easily too much rpms. My prop is a bit too small diameter now. I don't know how much this will affect to rpms or speed. I've been really careful last summer with rpms not to exeed the maximum.

My idea is to change the prop to the original one. I got the answer yesterday from Four Winns that original is 15x17 aluminium for my boat. I'll get one of these asap and get the boat to the lake...I have to buy another tachometer to have more reliable info about rpms.


Here is also a Jeep driver
Mine is rusty 3,5 inch lifted 1995 Grand Cherokee with 5,8 litre V8 with 31x10,5 offroad tires..

If you go to the 15x17 it should drop your rpms by about 400 rpms, as long as the fuel and ignition systems are in good shape it should then have a higher top speed. Prop pitch is like gear ratio in a vehicle. Low pitch=numerically higher gears, higher rpm/lower speed.
You just to make sure the boat hits it's specified max rpm so the engine does not labor getting up on plane.

Yes we also like our Jeeps.. The 07 Hemi is mine the 98 4.0 six is now my sons, both ride the beaches of Long Island NY...
I believe yours is a 5.2 liter (we used to say 318 cu in) V8... Old school Mopar power...

_________________
88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II