1976 Johnson 70hp won't budge

[pilotboyle]

I just bought a pontoon boat in need of refurbishing, and it has this Johnson outboard engine on it. First, I wanted to see what state the engine was in so I removed the cover and sparkplugs. Then I sprayed WD-40 in all three cylinders and tried to rotate the flywheel with a 1 3/8" socket and large ratchet. The nut loosened before the flywheel would turn. I tried reversing direction and got no movement. I made sure the lower unit would spin freely in both directions, and visually checked the cables to make sure it was in neutral. Apparently, the engine is locked up from sitting for years. What should I do next in an effort to free up this engine?

 

[James R]

Re: 1976 Johnson 70hp won't budge

WD40 wont do a thing for you. Shoot some Marvel Mystery Oil down the plug holes and let it soak overnight then try turning it clockwise only. If it still hangs up soak it again.

 

[tashasdaddy]

Re: 1976 Johnson 70hp won't budge

sounds like you are in for replacement or a rebuild. if it is stuck that bad, it is rusted up.

 

[CharlieB]

Re: 1976 Johnson 70hp won't budge

You are assuming that the motor is locked, what if it is the vertical shaft in the gearcase?

Try droppping the gearcase and see if the motor turns. If not, then keep soaking the cyl with Marvel Mystry oil. You might pull the motor off the boat and set it on the floor with the spark plug holes up then the oil will flow fully around the piston, wetting ALL AROUND the rings.

Bump the flywheel ring gear CW with a rubber mallet daily. Bump, NOT WHACK. Eventually it will turn. Have patience. LOTS of patience.