Engine Problem 2004 150hp Johnson

[bajaretired]

After running at 4000 rpm for 15 minutes the engine started missing and running ruff. I put the engine in neutral and the rpms went down to 1000 and then the engine raced back up to about 3000 rpms. I shut the engine off and waited about 5 minutes before starting again. Everything seemed normal for about 3 minutes then the same thing happened. After the third try nothing. I had to be towed back to the launch ramp. When troubleshooting the problem I found that I was only getting one spark out of the top two cylinders and no spark out of the bottom 4. I'm getting the correct voltages out of the stater and what looks like the correct pulses from the optical sensor and 11.5V on the yellow red wire to the power pack and eliminated the kill wire. I replaced the power pack and have the same symptoms. Anyone have any ideas????

[boats.net]

Recheck stator voltage, run resistance test on stator, check optical timming wheel.

[bajaretired]

I checked the stater resistance and it checks good according to the manual. I checked the optical wheel for cracks and dirt -- it appears to be ok. I also cleaned the leds with denatured alcohol. Both sets of high voltage outputs from the stater reads 165+ volts.

[boats.net]

Check wires, coils and all ground wire connections.