1986 Johnson 30hp misfiring

[JMAN3569]

My motor was locked up when I got it from sitting up for a few years. I broke it free by pouring marvel mystery oil in the cylinders, then rebuilt the carb, changed the plugs and ran sea foam in it. Now it runs but is misfiring. I have spark on both. It runs good for about 15-20 sec then a big miss then runs and miss. I pull the plugs and they are black. Kind stuck at this point. I have a video I can try and attach

 

[steelespike]

Re: 1986 Johnson 30hp misfiring

Sounds like a lean sneeze. Carb may need a careful check that all passages are clear.

 

[JMAN3569]

Re: 1986 Johnson 30hp misfiring

It missing about every 3 sec not 15 and i have rebuilt and been threw the carb to many times to count

 

[F_R]

Re: 1986 Johnson 30hp misfiring

My motor was locked up when I got it from sitting up for a few years. I broke it free by pouring marvel mystery oil in the cylinders, then rebuilt the carb, changed the plugs and ran sea foam in it. Now it runs but is misfiring. I have spark on both. It runs good for about 15-20 sec then a big miss then runs and miss. I pull the plugs and they are black. Kind stuck at this point. I have a video I can try and attach

Waiting for the video. I have some thoughts.

 

[Ricksmithy]

Was this problem resolved? I think mine has a very similar problem. All signs were pointing at CDI ignition but the problem persists after replacement of ignition components.

 

[racerone]

Maybe is jumping out of gear ???

 

[GA_Boater]

Was this problem resolved? I think mine has a very similar problem. All signs were pointing at CDI ignition but the problem persists after replacement of ignition components.

Waiting for the video. I have some thoughts.

The waiting comment was 5 years ago. F_R is still waiting. Start a new thread, Rick.

Closed.