Prop q

[Flyin1500]

Howdy!

I have a 1984 Mercedes 17' open bow runabout w/a mercruiser 120 hp I/O. Currently I'm running a 15X17 alum. prop. The manual says that wot rpms should be between 3900-4300. WOT now is 4800 w/ top speed 28ish knots (gps). I would like to get the wot rpm's in the range to get a better top speed.(and not explode my motor!) I'm thinking 15X19 to start. Also what would an increase/decrease in diameter do for things...like going 14 3/4 X19 or evern 14 3/4 X 21? How about ss? I plan on using the boat mostly for fishing so a higher/ more efficient top speed would be nice.


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[Bondo]

Re: Prop q

Your 2.5l motor will be Happiest when it's set up to run 4200/ 4600rpms at WOT..........

Forget about the new prop's Diameter,........ It's determined by the Blade Design,+ by the engineer that designed it.......
Do your shopping by the Pitch,........ The Diameter will work itself out.....
You really have Little or No Choice in the matter,....... So Forget about it.......

That Said,..............
I'd go buy a standard 19" prop,+ Go Enjoy it..........
That Should put your WOT right around 4400/ 4600rpms........

 

[Flyin1500]

Re: Prop q

Thanks for the info!