looking for input if you guys can help

[my1stboat1]

1988 16 foot bayliner center console 85 hp force....

old prop was aluminum 13 dia x 17 pitch Wot trottle rpms were 5000/5100 and top speed was right at 30/31 mph My ? is... I just bought a michigan Stainless steel prop 13 1/4x 15 pitch... What if any do you guys expect as a change.. possibly better or worse..


thanks in advance..

 

[Frank Acampora]

Re: looking for input if you guys can help

Well, The decrease in pitch will raise the rpm by about 400 to give 5500. the stainless will run about 200-400 faster than the aluminum, giving 5700-5900. However, those Michigan props are usually cupped which will drop the RPM to somewhere around 5500-5700.

If cupped: The cupping will allow you to use more out or up trim if the engine has power trim. If no power, then you may be able to set the tilt bar one hole further out. This will increase performance some.

HOWEVER: Sometimes, decreasing pitch on a Force engine while raising RPM may actually decrease top speed--Don't be surprised if you lose about 2 MPH. I'm not saying it WILL happen, just that it MIGHT happen. Best thing to do is try it!

 

[Home Cookin']

Re: looking for input if you guys can help

I'm testing props and when I went from 17 pitch alum to 15 pitch SS, I got higher RPM, better speeds at the same rpm at the mid range, but lost a couple mph at the top. I'm not concerned about the top end performance anyway, but I know that the top end is where you test/confirm your prop fitting

 

[my1stboat1]

Re: looking for input if you guys can help

thank you guys, i will try it out but it may not be for like another month stll little to cold on the water but i will get back to you guys and let u know


the prop is cupped and the boat does have power tilt/trim