1950s Johnson 5.5 only runs on top cylinder

[LargemouthBass21]

got a free motor from a friend he said he couldn’t start it. I got it running with some fresh gas, but doesn’t run good. I noticed it had brand new looking spark plugs, I checked them and the top was powdery white (lean) and bottom was completely clean (not firing). Anyway ur has extremely good spark (ignition was completely redone by a marina recently, even has the German coils) I noticed old sticky oil all over the bottom of the cylinder head, do you think it could be a bad head gasket? It would make sense since that’s the cylinder not firing. Also after it runs and dies I hear a hissing from the pressure tank, is there a way to test for pressure leaks in these old style tanks and make sure the pressure from the engine is working correctly?

 

[F_R]

Pour some soapy water over the tank to find the leak.

 

[LargemouthBass21]

Pour some soapy water over the tank to find the leak.

Ok thanks!
When I find it do I have to redo the gaskets or how does that work? Got any idea about the other stuff?

 

[LargemouthBass21]

Anybody?

 

[Crosbyman]

do compression test and post results ..both .cyl should be close to equal something about 75psi would be nice​

find and fix the air leak on the tank but hand priming is enough to start the engine… you need to get that going ​

no need to pressure test if the engine runs good after your fix ​

you could.… convert to a pump.. and use a conventional tank not a big job but ...you need to find a 2 pin engine side connector for modern single hose fuel line ​

one engine I converted years ago still runs perfectly ​

https://www.youtube.com/watch?v=ojOMbwvH55I​