johnson 25 runs hot, then rough

seminole

Recruit
Joined
Sep 2, 2008
Messages
1
new user to boating and forums - be easy on me!

I have a 1997 Johnson 25 which has been running fantastic. However, the last two times I have taken it out I am experiencing the same, repeatable problem. Starts fine with a steady water stream at all speeds. After a short while the temp alarm sounds and it immediately starts running rough except at idle speed. It cools off and immediately it runs like a top again for about one minute. As soon as the temp alarm sounds it immediately runs rough again. I thought the steady water stream represented a cool engine? Thanks in advance for any help/comments.
 

Harker

Chief Petty Officer
Joined
Sep 21, 2003
Messages
452
Re: johnson 25 runs hot, then rough

That is just an indicator that the impeller is pumping water. It sounds as if your motor is either getting hot and going into S.L.O.W. mode or a sensor in the S.L.O.W. thingy is faulty. When it does it, can you put your hand on the head of the engine without getting scalded? You may have some debris in your water passage if it is too hot to touch.
 
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