1998 200hp Oceanrunner missing on 2 cylinders

[CurrentAdventure]

I have a 1998 200hp Johnson Oceanrunner, carbed, that is not firing on two cylinders. I have taken it to my mechanic and he is baffled. According to the phone call I received this morning, it has fire, it has fuel, it has compression. Compression on all six cylinders were within 1lb of one another. He said it acts like it is in slow mode, but he has tried everything that he knows and cant' figure out why it will not fire on those two cylinder. I'm not sure about number order, but looking at the motor, the middle cylinder on the starboard side and the bottom cylinder on the port side are not firing.

Any ideas or suggestions are welcome.

 

[Chris1956]

Re: 1998 200hp Oceanrunner missing on 2 cylinders

SLOW mode kills spark to one bank of cylinders. I would try another mechanic.

 

[jonesg]

Re: 1998 200hp Oceanrunner missing on 2 cylinders

SLOW mode kills spark to one bank of cylinders. I would try another mechanic.

hahaha ditto. Get your boat outta there before he tries fixin it.

Just a guess, it looks like it has spark but spark is too weak, he doesn't know how to do a gap test.

Go to autozone, get a $10 spark gap tester, set the gap to almost 1/2 inch, just a tad less and I bet those cylinders will not sprak across that gap.
Look at the coils, remove and rotate in your hands, see any cracks?
Very simple fix.

 

[daselbee]

Re: 1998 200hp Oceanrunner missing on 2 cylinders

I would like to add to jonesg's excellent advice.
When you take the coils off to inspect as he suggests, be sure the coil to block mounting bosses are completely free of any corrosion. That goes for the mounting screws, star washers, etc. Gotta be a corrosion free electrical connection to the block.