12 1/4?

[dvrdwn]

i found some #'s on my 12" stainless 3 blade prop. 12 1/4 i'm assuming is the pitch. 18636 is another # the 36 i'm not sure about. There are also 2 dots above the longer #. any ideas

 

[steelespike]

Re: 12 1/4?

What does the prop fit? Numbers may refer to the cup or rake or perhaps simply the application.If you have the diameter,pitch and motor application
thats about all you need especially if you have some performance numbers.

 

[dvrdwn]

Re: 12 1/4?

79 55hp johnson 12" diameter 12 1/4" pitch no tach but sounds like it reving high 6000-6500

 

[Silvertip]

Re: 12 1/4?

12-1/4 is very likely the diameter of the prop -- not the pitch (which would be a very rare measurement since fractional pitches are indeed rare). You can verify that using a trusty device called a ruler. Measure from the tip of a blade to the exact center of the prop shaft and multiply by 2 if the prop is a three blade. If it's a four blade, measure across two opposite blade tips. When buying props, look at those for your engine make, year, and HP. Diameter will then take care of itself. You only need to be concerned with pitch.

 

[dvrdwn]

Re: 12 1/4?

well the only numbers on the prop are under the nut and washer. one number is 12 1/4 and 18636 not sure about the 36. i was assuming the pitch was 12 1/4" do to the ease of measuring the diameter.