1970 40hp evinrude prop

[petryshyn]

Hi Gents
I have a spun prop from a 40hp big twin. (pin drive brass prop) Can it be rehubed? Are there aftermarket props available? There are no markings on the prop. What was the typical pitch for that size when mounted on a light 14' fibreglass?


Thanks

 

[petryshyn]

Re: 1970 40hp evinrude prop

Anyone?

 

[Frank Acampora]

Re: 1970 40hp evinrude prop

Yes, it can be re-hubbed, but the problem will be finding a prop shop with a hub for it.

A simpler solution would be to drill through the hub and internal prop body from the back (at an angle and from the inside) in three places, 3/16 diameter, then tap the three holes 1/4 X 20 to receive three 3/4 inch long stainless setscrews. This will make the prop into a solid hubbed prop. I have done it on a couple. I started with 1/8 brass brazing rod and sheared them while tapping the gravel bottom. Then I went to 3/16 stainless cotter pins and almost sheared them under normal running. Now I use the setscrews. So far I have not hit bottom so I can't comment on how well they hold up

Now I've done it. The naysayers and gloom and doomers will come on posting how this will damage your lower unit if you hit anything. What is your alternative? Buying a used prop on ebay which may spin a hub too? buying a new one--if you can find it?

"Pinning" your prop will only cost 2 bucks for the setscrews and it will last forever.

Typical prop pitch on a small hull would be about 12 to 13 1/2

 

[steelespike]

Re: 1970 40hp evinrude prop

The 1970 brochure indicates motor came with a 10 1/2" X 12".
The primary consideration is the pitch the diameter will follow
based on the individual prop design. Frank hit it on the nose.I would stick with the lower number as you can use if its too light by watching to not over rev.If to heavy you should just plain not use it.A prop shop can measure your prop.
A good bronze(brass) prop will likely outperform a similar al prop.

 

[petryshyn]

Re: 1970 40hp evinrude prop

Thanks Frank and Steelespike.

I got lucky and found an old prop guy who has about 40 of these old style props in stock for $220 each. New brass ones.

Thanks Steelespike for the pitch as he has several pitches to choose from....

 

[Frank Acampora]

Re: 1970 40hp evinrude prop

A little pricey considering they sold for about 25 bucks back then.