correct prop for an 86 mercury 50HP 2 stroke 3 cyl.

a_ockels

Cadet
Joined
Sep 19, 2011
Messages
27
I will provide as much detail as I can. mostly I am worried about the original prop for this motor as a starting point, if someone has a suggestion feel free to give it. the prop thats on it has no markings left and is chewed up pretty good. I want to spend the money on a SS prop but don't know what size or pitch. in the water at WOT it seems to rev a little high but I haven't been able to get the tach to work. it cavitates occasionally on turns but I think that's fairly normal? this is my first boat so forgive my ignorance.
the boat is a 16 ft fisher circa 83 it's a fairly heavy semi v the cavitation plate is just below the transom. I'm not worried a whole lot about max speed I just don't want to tear up the motor as after much cash and work it has been running really well.
I am working on getting a diff. tach but I fear basing anything off of the chewed up prop. and I also don't know it's size or pitch. the largest ss prop I have found for my motor is a 11" 15 pitch.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,780
Re: correct prop for an 86 mercury 50HP 2 stroke 3 cyl.

Michigan Wheel for one has a thorough prop lineup for most marine engines and can give you an idea as to which prop is right for you. Non conclusive, nothing is till you run it, but it could put you in the ball park.

Mark
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: correct prop for an 86 mercury 50HP 2 stroke 3 cyl.

A prop shop can repair it and tell you the size.
Then you could test run it and get the rpm and the speed by gps.
Also the size is probably under the prop nut.
My 50 Evinrude has a 19" on my much lighter boat at 375lbs dry weight.
My guess is that if your boat is glass it will use about a 15" prop. but don't get a prop based on my guess.
 
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