Johnson 115 HP mfg: year 2004

[Larry Gustafson]

Need help in solving problem with the engine running rough at 4500-5000 rpm
and then slows down to about 3500 rpm but can run engine at slow rpm 1800 rpm, have change spark plugs, changed out fuel line with primer pump, clean fuel filter on engine, changed out in line fuel filter also. will wait a day and start the engine and can run it up to 4000 rpm's in nuetral position.

Please help me !! Thank you for your support

Larry G.

 

[jonesg]

Re: Johnson 115 HP mfg: year 2004

Don't run it up in nuetral, without a load it will damage something or runaway on you.

Check for spark on all cyl's, sounds like its not firing on all holes.
Go to the auto part store and get a $10 spark GAP tester, set the gap to almost 1/2 inch and see what the spark looks like. I think you'll find one with a weak spark.