Identifying a Johnson 5.5(?) powerhead

[phil-b]

I was given a JohnnyRude 5.5 parts motor: The S/N and cover are from a 1964 Evinrude, but the block has the ID "plug" from a 1966 6hp (which was clearly pryed out at some point), and under a layer of spray paint, the block is white, so I’m thinking it came from a Johnson. With a rope on the flywheel, it tested at approx 68 PSI on both cylinders, which seemed promising enough. The LU had no lube, just rusty water, so I have hope that saved the head from excess abuse.

This is my first 5.5, so I don’t know anything about the evolution (what changed in what years).
The head has a thermostat, and threaded holes for a fuel pump, so that would seem to rule out 1959.

Without disassembly, how might I tell what year it was made?
What was the last year Johnson blocks were white?

[jeff-register]

Phil,
I know the 59 was white & looked good too!!!
Jeff

[frankr]

1959 had a thermostat, 1960 was first year for both a thermostat AND a fuel pump. At some point, the white was changed to that grey-ish off-white color called French Silver. I don’t know what year that was. If I’m thinking correctly, 1967 was when they went to green.

[fleetwin]

I’m confused, you say the block the ID plug from a 66 Johnson, so I would assume it is from 1966. Or, are you saying someone pried out the original core plug from this block and replaced it with the 66 core plug, but really don’t know why anyone would go through that much trouble. Perhaps the ID core plug fell out into the pan and the marks you see are from someone trying to secure it in place by peening the aluminum from the block over the plug slightly.
In any event, the 64 models used the top mounted recoil, so the intake manifold would have to be changed in order for a 66 6hp powerhead to fit. What color is the intake manifold? In any event, the cylinder head changed a bit on the 6hp, but that might have been switched over as well. The 6hp head has a slightly different cooling passage/thermostat cover and the plugs are installed on an angle.

[phil-b]

It looks like there are two threaded bosses on top of the block, and the intake manifold has two arms, one on each side.
The block seems creamy white, as opposed to greyish.
The ID core has a hole at the edge, as if it had been pried out with a flat blade screwdriver.
The whole engine has been (badly) sprayed with metalic blue paint a good deal lighter than typical evinrude blue.
The spark plug hold go straight back.

It seems pretty clear to me that it’s a Johnson 5.5 head.

I was just wondering what (if any changes) there were between 1960 (has fuel pump mount) and 1964 (end of the 5.5).

[fleetwin]

Well, the biggest change was sometime in those years needle bearings were added to the rods. Sounds like your powerhead is somewhere between a 1959 and 1964, don’t know why someone would have added a 66 ID core plug.

[phil-b]

They could pass it off as a half-hp more?

And I get to wonder how long it was run on 50:1

[Author]

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