correct prop for boat?

zildjian29

Petty Officer 3rd Class
Joined
Jul 7, 2011
Messages
80
I have a 1985 stingray 17ft open bow. Powered by mercruiser 3.0 140hp. Has 13pitch prop now and its not right! Anybody happen to know what pitch is best? 17 or 19 maybe?
 

SkiDad

Lieutenant Commander
Joined
Jul 18, 2010
Messages
1,518
Re: correct prop for boat?

i would start with a 19.... it's probably your best guess.
 

jestor68

Commander
Joined
Jun 12, 2012
Messages
2,308
Re: correct prop for boat?

Take another look and provide the diameter and pitch; It's stamped on the prop hub; something like 15 X 18, for example.

A 13 pitch wouldn't make any sense for that boat.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: correct prop for boat?

I agree the 13" is the wrong prop but how does it do with it. Lightly loaded wot rpm and gps speed.
Should over rev easily.
What is the gps speed at 4800 rpm?
Some cell phones have a gps app.
I do agree a 19" is a good starting point.
 

zildjian29

Petty Officer 3rd Class
Joined
Jul 7, 2011
Messages
80
Re: correct prop for boat?

Over revs easy and only 20 mph with GPS. Think a 19 is still good for pulling tubs etc.?
 

SkiDad

Lieutenant Commander
Joined
Jul 18, 2010
Messages
1,518
Re: correct prop for boat?

20 mph doesn't sound right even for a 13. I would think more like high 20's. Does the engine run ok. With a 19 I would think 35-40 mph. And tubes are easy to pull
 

zildjian29

Petty Officer 3rd Class
Joined
Jul 7, 2011
Messages
80
Re: correct prop for boat?

It could have been low 20s! Engine is great compression in all cylinders is 130. Runs good. I will try a 19 don't think 17 would do it! Thank you. My first inboard always had smaller outboards!
 
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