97 Johnson 150..losing RPM

[Tortuga]

Have a 150 HP Johnson Ocean Runner, approx 300 hours on it. Well maintained. Usually cruise at 4000 RPM..wot is about 4800..After 6 years, having trouble getting to 4000, even at WOT. Boat has been idle for about 2 months. Replace plugs and am having trouble checking choke (primer). Also seems to be dripping a little gasoline around where I think choke is, but mechanic checked it out and said it was OK..Any suggestions appreciated...Jim D

 

[MikeMoonpie]

Re: 97 Johnson 150..losing RPM

I have the same motor, only a 98 model. Mine had problems I believe traced to the carbs, and leaned out #6 cylinder. It is currently dismantled, awaiting a trip to a machine shop to bore all 6 cylinders, and replace 6 $100 pistons.<br />You might want to check the compression, and then the carbs. My first suspicion was the oil injection, which I intent to take off to reduce my fears of it quitting. I have heard many do this, and 50 to 1 mixing is not rocket science.