Hey guys,

As a side project from my Formula I just picked up a 78 johnson el55, this motor I got through my grandpa and sat unused for 10 years or so. I removed the spark plugs and shot some WD40 in there to lubricate it a bit, and spun the engine over by hand with no plugs. It seems to turn freely until the #1 cyclinder gets to TDC and then it feels like the flywheel skips and the tension is release.

I removed the lower to eliminate a frozen lower unit and still acts the same. When I try to crank it over with the starter but without spark plugs it spins great. Then I replaced the lower plug and still spins great. Its when I replaced the upper plug it binds up, and stops rotating completely. I replaced the starter (because it broke when I was cleaning it up). After I replaced the starer it still binds up with both plugs in.

Any thought on what could be wrong?
I know this thing is old and not offshore at all, but I would like to salvage it for a lake boat for my kids.

Spins fine with no plugs.
Spins fine with lower plug.
Won't spin with top plug.

My guess is you are using a plug in the top cylinder that is too long and the piston is hitting it.

MC

I would go to offshore only and ask on that forum - all they do is outboards. With that said, you have to keep in mind that the bearings on the crank are also lubricated by the 2 stroke oil. So running WD 40 in the cylinder is not doing anything for them. They are probably old and need lube too so I would not be cranking the motor over too much. You will be able to see if you have the wrong plugs - just look in the hole with a flashlight and see if the plug was hitting the piston.

Something does not make sense to me on this - you are getting stuck at TDC - the only thing that would do that is some kind of compression issue which I would think is unlikely or a mechanical problem which I would guess is rust or other material stuck at the top of the cylinder. If it was me I would chack and see if I could find a head gasket for the engine and pull the head to see exactly what is going on.

Hey Mike......I assume you mean it is a 55EL78S model?

That should have a Champion L77JC4 or QL77JC4 in it. You can look them up online for a cross reference if there is a different brand, but make sure as stated previously your one cylinder doesn't have a plug that is to long in it,

I work with tons of outboards. PM if you need help. Also, try Iboats.com there is a forum there for every individual outboard brand. Free to join and alot of knowledgable people.

i think port monster meant scream and fly. but stick a piece of coat hanger or a screwdriver in and turn motor by hand. compare heights at tdc to make sure everything is same-same between cylinders. then try compression test. could be buildup is causing very high compression in the one cyl.

Yup - fruedian slip. screamandflydotcom.

Yup, I have the right plugs and no damage to them either. It's weird because it will crank fine with just the bottom plug installed and then when I thread the top plug in, even just a bit it will stop the rotation. So that leads me to believe it is a problem with the top cylinder (vertically aligned).

Port Monster, I'm think I am following your advice and pulling the head. But man that flywheel is really on there. I'm try to find a way to pull it off. I have gotten the top nut off and then been soaking the center with penetrating oil, but that thing wont budge.

i believe the motor need to have surface fire sparkplugs..

You need to use a flywheel puller or equivelant to remove the flywheel or you might damage the crank, DereknKathy has a good idea measuring piston travel if that thing sat that long the needle bearings on either end of the rod could be rusted & binding up. If that engine has a vro pump junk the pump & put a standard fuel pump on it those pumps were junk when new & now they are 5 times more expensive & still junk. Hope you get it running, Randy

Mr Fixxall is correct a QL16V or L16V fixed gap is what the book says