"92" Johnson V-6 150HP

[coy]

My 150 Johnson will start fine and run great for about 5 to 10 min. and then the HOT warning siren sounds and the engine runs rough. If I keep it at about 1000 rpm it still runs. I replaced the impeller and have ordered new thermostats. After alarm sounded I felt the cylender heads and they were cool. I visualy inspected the thermostats and they are open (you can see through them) even when the engine is cool. Any suggestions?

 

[R.Johnson]

Re: "92" Johnson V-6 150HP

Disconnect the tan wire's, one at a time at the top of the heads. These are the heat sensors, one, or both may be defective. This would put the engine into SLOW, just like a over-heat.