'99 Johnson 115 intermittent spark on all 4 cylinders at higher RPM

[Captain Jeff]

Hello, 1999 Johnson 115 Oceanpro stumbles or misses usually over 3500 RPM and sometimes at a lower RPM when you are accelerating quickly. The engine runs flawlessly at lower RPM. I got a timing light and checked each spark plug lead. The light was flashing normally at the lower RPMs but definitely missing/ not getting spark when the motor was stumbling. It seemed like it would miss a couple sparks and then spark and so on. I think I've narrowed this down to an electric problem, everything else is good...fuel, compression, etc. Whats wrong with this motor!??

 

[bennysku]

Re: '99 Johnson 115 intermittent spark on all 4 cylinders at higher RPM

Did you ever figure out what the issue was on this one? I have a similar issue on a '77 140hp Evinrude.

 

[clint]

Re: '99 Johnson 115 intermittent spark on all 4 cylinders at higher RPM

Did you check your ignition wires? If they are older than a year they can get dryrot and jump, ground out to the inside of your cowel cover. I had this issue with my 140 evinrude. I had to replace with new ignition wires and no more missing or cutting out. Good Luck!
Clint8)

 

[muskrat]

Re: '99 Johnson 115 intermittent spark on all 4 cylinders at higher RPM

you are going to have to get a service manual to check voltage output in igntion.