JOHNSON RUSTY PLUG

hi guys. I just got a 70 hp,1976 johnson o/b ,3-cyl. I was changing spark plugs, and the bottom one was rusty. what does that tell me. Also the starter motor clicks and wiggles whaen i try to start it. should i be able to start it with a pull string, because i can't. Thank you.

Re: JOHNSON RUSTY PLUG

Get a bore light like what you would use for a rifle, and look in the cylinder and see if there is rust in there. Or you can pull the head off. If so, that is bad news. That means water in the engine. That means that the rings are rusted, and the bearings on the bottom cylinder. If that is the case, unless you are very handy, and have a good manual, it is time to scrap it.

Re: JOHNSON RUSTY PLUG

If you are saying the part of the spark plug that resides inside the motor was rusty, than that somewhat explains why it's not starting, or even turning over well, or at all.<br /><br />Sounds like water has found it's way into the cylinder and rusted the piston rings to the cylinder wall..<br /><br />If that's the case, it can't be good.<br /><br />Perhaps some light penetrating oil might get it free'ed up enought to spin over. But I would suspect that after being frozen (rusted) up for any lenth of time internal damages might have set in. (cylinder wall pitting and perhaps piston ring sticking, ect, ect)<br /><br />Of course if it's just a bit of rusty deposit, and you feel that no internal problems exist, it could be a head gasket or exhaust cover gasket that's causing it.

Re: JOHNSON RUSTY PLUG

looking through the spark plug hole the top of the piston isn,t rusty. it is just the part inside the engine that is rusty on the plug. if the cylinder wall is corroded is it rebuildable. never worked on boat motors, have clymer manual b736.

Re: JOHNSON RUSTY PLUG

If they cylinder wall is rusted, it is rebuildable, but that would probably require a boring job and an oversized piston what all the other hardware. Rebuilding that motor would not be worth it, when you can find those motors all over. It would cost more to rebuild than it would cost to buy another one just like it in running condition.