If a prop fits, does it fit?

[ryangrady]

Hi all, my boat, a 1974 19' Neptune with a GM 250 inline six and an electric shift sterndrive, came with two props. The prop that was on the drive when I bought it is marked "14 1/4 10". Another prop that I found in the boat is marked "14 14". I'm guessing that the first number is the size, since on the 14 1/4 prop the body loks a little larger, and that the second number is the pitch. I never really thought much about it until reading about prop selection here. I don't pull skiers, and spend most of my time cruising from one fishing spot to the next, so lower cruising rpm's sounds good to me. Should I be concerned with the first number, which I took to be the size? Both props fit on the shaft just fine. Thanks for any help.

 

[cobra 3.0]

Re: If a prop fits, does it fit?

That's a large change in pitch from 10" to 14". Your engine should fall in your engine's recommended maximum rpm range when you are going full out. If it rev's higher/lower don't use it.

 

[Cobra SX]

Re: If a prop fits, does it fit?

Ya dude that is a change of 4'' witch is a big step, but not nessesarly a bad thing, you can do the math out. RPM's decrease using a higher pitch, if you have a tach check your WOT.<br /><br />for every 1'' you go UP your RPMs drop 150-200<br /><br />and for down its about the same(thats the theory)<br /><br />So a prop change for you would range up yo 800 Rpm's So beeee careful...<br /><br />So find the WOT of your boat. because that is what you want to know. (WOT = wide open throttle)