Re: 1989 50hp Mercury oil in exhaust plug fouled
Here is what I did this weekend. I started the motor and disconnected the bottom cylinder plug wire, no change. I put it back on and disconnected the middle cylinder plug wire, engine stumbled. I put it back on. I then disconnected the top cylinder plug wire and engine stumbled. Next I took the middle cylinder coil and swapped it with bottom cylinder coil. I started the engine and removed bottom cylinder plug wire still no change. I removed middle cylinder plug wire motor stumbled. This eliminates the coil as the problem. Here is where it starts to get tricky. I pulled the plug wire on bottom cylinder and could see and hear the spark to the plug, but no change in engine cylinder definately not working (I'm thinking spark is too weak). Then I rev the engine up and try to change the situation. Next thing is I pull top cylinder plug and no stumble. Now the top cylinder has no spark. I pull bottom cylinder plug wire no change. Engine is now running on only one cylinder the center cylinder. I am thinking that the only thing that could cause this condition is the switch box. The part is $185 new from the parts store. I do not have a dva to test but was wondering if it sounds like the switch box to you experienced folks. Carbs are clean as a whistle and fuel is flowing nicely. Any help would be much appreciated and I will continue to post resolution in order to help others. Thank you.
