1998 Johnson 115 cylinder 4 no fire.

[GACraig]

Hello, I'm looking for a little assistance identifying a problem with my 1998 Johnson 115 SPL. The #4 cylinder is not firing, for one reason or another. I have replaced the coil, wire, plug (all 4), CDI box, trigger, set the timing according to specs, and I have spark on #4. I can run it a few hours, pull plugs and compare, and the #4 plug comes out squeaky clean, while the others appear darkened and used. Every now and then, it will fire on all 4, run like a champ for a half a minute, then drops off and obviously loses a cylinder. When it runs on all 4, it runs around 42mph, but drops to 32mph tops, when it drops that cylinder. Compression on all 4 cylinders is very good. I've run out of electrical issues to address, and still have the same problem. So, it must be a fuel delivery problem, I am thinking. What do y'all think? What do I need to check now? Thanks in advance.

 

[CarMech1969]

Carburetors, or fuel injection??

 

[Boobie]

Got a model # ??

 

[GACraig]

Carbs

 

[GACraig]

Got a model # ??

I do, but not on hand. I dropped the boat off at a friends' house this afternoon, to see if he can figure it out. I THINK the model number is
J115FSLECS
if my memory serves correctly. I cannot swear by it though.

 

[flyingscott]

You gave us the model # of a Ficht DI motor. Since your motor is an spl I am goint guess you have a 90deg crossflow motor. What are the compression #s? Does spark jump a 7/16" gap? Have you done any trouble shooting on the ignition. Have you checked for spark when the problem happens? www.cdielectronics.com has the troubleshooting guide for your ignition. Now if you have the 60 deg looper same questions. If you actually do have a ficht my condolences.

 

[Boobie]

Don't THINK. Get the correct model # for correct answers back to you.