Prop size

B

blue.monkey

Seaman Apprentice
Joined
May 22, 2002
Messages
34
I have a 21' Bayliner Trophy, I replaced the Force 125 with an Evinrude 150, (1989), When I put it in the water I found that it will not go over 3500 RPM, and takes about 15 seconds to get there, (bogging). I am thinking the prop is to aggressive. The prop on it is a 15 x 17 x 3 as read off the prop. any ideas if this is to aggressive or what I should try? <br /><br />Thanks,<br />Blue Monkey
 
T

tazatax

Cadet
Joined
May 21, 2002
Messages
15
Re: Prop size

blue.monkey,<br /> first what was the prop size on the 125<br /> second what size boat did the 150 come off of?
 
Boatist

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: Prop size

I think you have wrong prop also. I have a 20 and 1/2 foot Aluminum Runabout a much lighter boat with a 140 motor and the correct prop is 13 3/8 17 by 3 blade. I think your motor is a little small for that heavy a boat and bet the pitch should not be over 13 for a 15 inch dia. Add about 400 rpm for every two inch change in pitch. I would go to your bayliner dealer and a evinrude dealer or better yet one that does both and ask them. They should have some basic HP / Speed charts and be able to tell you right prop. Also many dealers if you buy prop from them and it is wrong size will let you exchange for correct size.
 
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