1972 johnson 50hp-- several questions...

jbjennings

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Joined
Jul 18, 2007
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Background:
Bought motor, trailer, boat, with all papers for $100. Motor was in a flood at one time and never restarted. Hasn't been since about '87.
IT is hydroelectric shift.

Motor was a little sticky but after a little wd-40 in the plug holes and practically no effort, it immediately turned over very smoothly with no binding. Spark plugs were clean with no rust whatsoever. I don't believe any water ever got into the motor the way it looks/acts.

Got starter working, works fine with plugs out, but lethargic with plugs in. Motor does shift into neutral when starting. Needs starter rebuilt? It is the same whether starting with key or by jumping directly with battery.

Compression is great on bottom cylinder at about 150 psi. The top cylinder pumps up slower and only gets about 110psi. Could it be a head gasket possibly? No change with oil in top cylinder.

I haven't rebuilt carbs. I am getting at least some spark and a weak attempt at a start with one plug out (starter doesn't spin fast enough to start with both plugs in) and a smoky backfire through the carb now and again.

Main questions: should I trash this motor? Is it worth a head gasket to see if compression will come up on top cylinder, or is that most likely NOT the problem?

IF I were to get it running, and wanted to change the impeller, is it almost assured I will booger up the wiring to the hydroelectric shift even if I follow the correct procedure?

Just interested in how far I would be wise going with this motor. The boat is astonishingly strong everywhere on floor and the bottom of the hull is flawless; the gelcoat is even shiny and doesn't even have the slightest scratch.
Is it possible there's a brush or something not making contact and making the starter weak?
Thanks for any help,
Will hopefully report some new info late tomorrow. I may take the exhaust cover and head off to look for stuck rings, cylinder gouging, etc.
JBJ
 
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