How do I determine correct prop?

[jsouthco]

I have a 1969 Evinrude 18 hp motor sitting on a 14 ft aluminum Crestliner (1955). How do I measure the prop and what would be the correct size for this ?<br /><br />Thanks in advance for any help!

 

[Bear]

Re: How do I determine correct prop?

1968 18 hp propellers<br />9 x 10 1/2 opt.: 9 x 10 , 9 x 9<br />1971<br />9 x 10 opt.: 9 x 9<br />Same gear ratio over the years.<br />Do you have a prop for it now?<br /><br />I don't know how heavy your boat is. <br />10" or 9" pitch, you'll have to try one first.<br /><br />Measure from center of the prop to the tip of one blade. <br />That will be 4.5" <br />4.5" x 2 = 9" That is the diameter.