best prop for a 1975 Evenrude 15 horse

Magboy

Cadet
Joined
Oct 17, 2015
Messages
6
I'what would be the best size prop for this motor. It's on a 14' Valco aluminum boat.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
We need more info on your typical load and activities.
Your present prop should have the size near the base of the blades or on the hub.
Also would be helpful to have your present lightly loaded wot rpm and gps speed.
The 15 is capable of 5500 - 7000 wot rpm.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Need to test current prop minimum loaded on flat calm waters with an induction tach and check if inside wot rpm range, can go from there maximizing a prop to suit your boating applications and loads.

Happy Boating
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
The 10" pitch prop that came on it is a good choice for most 14' boats.

Only a tach at current load will tell specially if liking running at constant wot for a "Long Live the OB" Could be lugging the engine and not knowing anything about it. Fast displacement speed on large boats is a different story. Not much prop selection to choose from.

Happy Boating
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Is there that many to choose from?

There are 5 basic sizes,7,8,9,10,11 each size has 4 - 7 designs.
If you run the boat empty a 10" is probably the one you want.
A 10 comes in 7 choices.Assuming a healthy motor and correct setup a cheap 10" will probably work.
But it is important that the motor be able to operate within its wot rpm range.
To get us started if you get us the present size and the lightly loaded wot gps speed we may be able to get an idea how your setup works.
without that info we can't tell what you may need.
 
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