3hp Johnson Prop Question

[david-bartlett]

I am just wondering what the difference in performance might be between the 2 blade prop and the 3 blade on a Johnson JW 3hp?

Any thoughts, ideas, etc.

Thanks, David

[jerry-ahrens]

I believe the 3 blade prop is a larger pitch that would be suited better to a light load. I know one of the two props is a higher pitch than the other. Someone please correct me if I have that backwards.

[frankr]

I think you got it backwards. Hopefully Garry will be along and straighten us both out.

EDIT: Heck, all I had to do was look in the book. The 3blade prop was 6 1/2 dia x 5 3/4 pitch. Two blade was 6 1/8 dia x 6 1/4 pitch.

EDIT EDIT: The two blade used on the 1970 4hp weedless was 6 3/8 dia x 5 1/2 pitch. Verrrry interesting.

EDIT EDIT EDIT: er..maybe that was a 3 blade on the 4hp. Book doesn’t say.

[outboard315]

Most likely not much to report on performance since its only 3 hp and you are not changing pitch that much. However the 3 bladed prop is likely to over wind on a light boat or canoe. The 2 bladed prop came out to help from over revving. If you are looking for performance I believe a 4hp powerhead fits in the place of the 3hp.

[fleetwin]

Well, I have often wondered about the same thing. Tried the two different props on my 58 Lightwin, didn’t seem to make much difference.
There were two different 3 blade props used on these engines, the one from the 50s has less pitch than the one introduced in 69 for the 4hp.
Funny, I thought I remembered the later 4hp prop being closer in pitch to the two blade, although just a little bit less. Will have to look.

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