Johnsorude 4Hp (1970s) Plastic prop?

9D280 · 08 November 2012, 08:58

Could someone with one of these post a pic of the prop?

I noticed last night as I was messing about at the transom that my prop blades at the tip the blade surface appears to be pretty well aligned with an imaginary disc perpendicular to the shaft - if that made sense?

I've always thought it was a little lack lustre, which I had originally put down to it's age, but I am now beginning to think it might be the plastic prop has warped with age.

Can anyone post a pic of their prop? It's the 'Rude / Johnson twin pot 4 from C. 196Oatkake - C. 1974.

Thanks.

HUMBER P4VWL · 08 November 2012, 09:43

Will try tonight. I have an old 70's white j'son. Not sure if a 3 or 4 as all decals gone. It has a black plastic prop though.

jyasaki · 09 November 2012, 16:03

Are the blades separate from the hub?

Some plastic props have blades that are adjustable for pitch; could it be that the detents are gone and the blade has slipped?

jky

Nos4r2 · 09 November 2012, 21:55

You can get ally props for those, and the 2hp plastic prop also fits them.

HUMBER P4VWL · 10 November 2012, 00:19

Quote:

Originally Posted by Nos4r2

You can get ally props for those, and the 2hp plastic prop also fits them.

Would it make it any quicker?

9D280 · 10 November 2012, 00:20

Jyaski
No, solid lump.

Nos.
Yeah, got one of them, but even lower pitch than the one on the 4, its the blade shape doesn't look right on the 4, especially alongside the 2. I did wonder about alloy, good to know its out there.

9D280 · 10 November 2012, 00:22

Quote:

Originally Posted by HUMBER P4VWL

Would it make it any quicker?

It's not so much quicker as a 4 with the same-ish effective grunt as the 2 it replaced.

9D280 · 19 November 2012, 22:06

A little later than planned, but here are the pics:

White gearcase is the 2HP - Blades the sort of shape you would expect - a curve on the tip to throw the water backwards.

Blue gearcase is the 4 - pic doesn't show it too clearly (trailer on axle stands at the mo so not easy access) - but when compared to the prop on the 2 it has a much "flatter" profile. (and the pic doesn't show it too well, but that top blade actually is convcave whenyou look at it form the front (as we are now) - and the cuurve isn't even across the three blades)