Johnson Overheats

Randy,

We have an í88 Johnson 90Hp VRO motor on our boat.  For the past two years, when I start the boat and leave from our dock, it runs at idle for five minutes, then the over heat alarm goes off.  So we would sit in the boat for about 10 minutes until it cooled off, start fine, and work fine all day.  To take care of the problem, I assumed the intakes were plugged with moss, so instead of a slow idle, I would put it into a fast idle until it could be ferried out of our long channel to the main lake where it could be put on plane.  No problem. 

Last week as we were taking the boat off the lake for the 4th (our lake is a great one to get off on the 4th because of the HIGH boat traffic) I was running wide open and it seized (the alarm did not sound).  However, at the time I didnít know what was wrong as I had never experienced that before.  After 30 seconds, it cooled off, started fine, and ran fine to the dock.

Last night I went out fishing.  The boat ran fine at idle and troll speeds.  I did not put it on plane until the end of the night, after dark of course, when it again lost power and died (no alarm again).  I was able to make it back to the dock, without incident, at idle speed. 

What is going on with this motor?  Is it a water pump? 

Could it have anything to do with the oil?  It doesnít seem to be burning a lot of oil, and the bulb is always hard on the oil tank, but I could just be paranoid at this point. 

Thanks in advance for your advice 

Dave Livermore
Forest Lake Minnesota

 

Dave, 

Sounds like your motor is "dead". By dead, I mean after the seizure the damage is done and every minute you run it after, will increase the repair cost exponentially. Have it rebuilt, as the piston or pistons are permanently damaged. Don't try to run it as this will only cost you hundreds more. Have a new waterpump and VRO Pump installed during the rebuild. It's going to take a couple grand to fix this, so sorry for the bad news. Cut your losses and take it in. Prepare for the worst. 

Randy

 

 

Please submit whatever questions you have to IHRTechTalk@yahoo.com.  All questions and answers selected will be displayed on this page as they come in.  Note: though all boaters are welcome, priority may be given to I.H.R. members.  Randy can not be held responsible for any advice given.  Though his information and expertise is second to none, he has no control over what you do with your boat.  It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.

Thanks,
Mark C.

 

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