Powerhead For 1958 Johnson Super Seahorse RDS-20

[sandman]

Hey guys,

I am doing a full on nut and bolt restoration on a 1958 Johnson Super Seahorse 35 HP RDS-20. The original powerhead and pistons are pretty much toast but the rest of the components are still in great shape. Does anybody know if a Powerhead from a 1959 Johnson Super Seahorse 35 HP is a direct swap? If not, is there an Evinrude model from the same year that would be a direct swap? Thanks for much for any help and advice. I have been researching and found that the 1957 Powerhead won’t work, I am hoping the 1959 Powerhead will work since there is one on Ebay reasonably priced right now. http://www.ebay.com/itm/VINTAGE-1959-JO … 5C&vxp=mtr

If anyone here has a 1958 Powerhead, I would be very interested.
Thanks,
Sandman

[frankr]

The ’59 should be a direct swap. Also, a 1958 Evinrude Lark is a direct swap for the 1958 Johnson SSH. Likewise, 1959 Evinrudes. If you want to sneak a 40hp in there, 1960-61 models will bolt up with minor mods.

[sandman]

quote FrankR:

The ’59 should be a direct swap. Also, a 1958 Evinrude Lark is a direct swap for the 1958 Johnson SSH. Likewise, 1959 Evinrudes. If you want to sneak a 40hp in there, 1960-61 models will bolt up with minor mods.

Thank you for the help, FrankR. I snagged the 59 Super Seahorse Powerhead off the ‘Bay after getting your reply.

[elgin2]

I have a 61 40hp Evinrude powerhead if that one doesn’t work. It needs a upper crank seal.

[johnny-infl]

SandMan – if you are going to be having extra parts during your restoration,
such as chrome pieces, medallions, etc etc, please contact me.
I have one that has some cosmetic issues.

[chris-p]

Johnny,

That stuff is getting harder and harder to get! I regret selling all my NOS medallions now, lol

Sandman, didn’t see this until now. I have a few fully rebuilt 35hp powerheads on the shelf that are primed and ready to be installed.

[chris-p]

Sandman,

I found a good powerhead for you. I have almost gotten it all torn down (1 darn exhaust cover bolt left that is being stubborn!)

I tested the bore, and it is true, with very minimal wear. Well within spec. It was a 125 psi motor.

Ill soda blast the powerhead tomorrow, assuming I get that last screw out of course. Hone the cylinder and paint it.

You will be back on the water by spring!

[Casey Lynn]

quote Chris_P:

Sandman,

I found a good powerhead for you. I have almost gotten it all torn down (1 darn exhaust cover bolt left that is being stubborn!)

I tested the bore, and it is true, with very minimal wear. Well within spec. It was a 125 psi motor.

Ill soda blast the powerhead tomorrow, assuming I get that last screw out of course. Hone the cylinder and paint it.

You will be back on the water by spring!

If it was a 125psi engine…..why did you tear it down?

[Casey Lynn]

quote Chris_P:

Sandman,

I found a good powerhead for you. I have almost gotten it all torn down (1 darn exhaust cover bolt left that is being stubborn!)

I tested the bore, and it is true, with very minimal wear. Well within spec. It was a 125 psi motor.

Ill soda blast the powerhead tomorrow, assuming I get that last screw out of course. Hone the cylinder and paint it.

You will be back on the water by spring!

If it was a 125psi engine…..why did you tear it down? At that compression the engine was well sealed to begin with.

[chris-p]

Couple reasons Pappy,

First he is doing a full blow resto on a ’58 SSH, and needs a powerhead. He bought all NOS components, but needed a good crank case.

I had a spare crankcase, which was good. The crank splines were damaged though, as was the keyway, so had to take it apart, even though the compression was so good. Im not skilled enough machinist to repair the threads and key way in situ on the motor.

So, everyone wins.

[Author]

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