84 Johnson 40 hp one cylinder not firing

[soccermatt22]

Even at start, one cylinder is not firing. Points, condencers, and coils all just replaced. There appears to be corrosion on the plug. Can anyone help me?

 

[soccermatt22]

Re: 84 Johnson 40 hp one cylinder not firing

This is a friends boat, I was just hoping that someone could help point him better than I did! haha

 

[G DANE]

Re: 84 Johnson 40 hp one cylinder not firing

I think you are incorrect on the year. 40 Hp Johnson should have CDI ignition since 1980 at least. Check and let us know. Did you check if there was spark on both ? If there is water on the plug, it can be a blown headgasket. Not firing on one cylinder can be a read problem too, among others. Can you give more info, Is there spark on both plugs, what is compression like ?