Diameter diff ?

21270

Petty Officer 2nd Class
Joined
Dec 10, 2004
Messages
104
Would there be any diff in mph & rpm's on a <br />13 3/4 x21 prop and a 14 x 21 prop on a 1993 merc 4.3lx gen 2.
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Diameter diff ?

Only if the drive is mounted high enough to take advantage of the diameter. I doubt it is to be honest. Now that's providing the props are the same brand and style. Are they both 3 blades or is the 13 3/4 a 4 blade?
 

Purduebarry

Petty Officer 1st Class
Joined
Sep 29, 2005
Messages
378
Re: Diameter diff ?

I asked the same question to a prop shop today. He said 1/4" difference in diameter is only 1/8" per blade, negligible amount won't really matter. I don't know if I got the right answer! <br /><br />My Dad always told me size does matter :p . <br /><br />Seriously, this small of an increment, can it really make a difference all other things equal?
 

budsbud66

Petty Officer 2nd Class
Joined
Feb 25, 2006
Messages
105
Re: Diameter diff ?

agreed the small amount wont hurt, but dont go to small, it is less efficent. An analogy would be.. would you wear a shoe thats too small just because it fit? ok maybe thats bad but you get the point. correct me if im wrong.
 

21270

Petty Officer 2nd Class
Joined
Dec 10, 2004
Messages
104
Re: Diameter diff ?

Thanks for the info, I didnt think it would make that much of a difference but I have been wrong many times before.
 
Top