[C320-list] Engine and Reefing Questions

[Jeff Church]

Mike,

The thermostat in the cooling system cycles between fully open and partially open at around 180 degrees, and the engine temp will vary a few degrees as that happens. 180 degrees is normal, but even 190 to 195 would be acceptable under heavy loads on a hot day in warm waters. I ran the engine at 3200 rpm for 13 hours on a 100 degree day. The boat was fully loaded for a long cruise and the bottom was dirty. The engine ran around 190 or 195 degrees all day long. I called Mack Boring (Yanmar distributors) to see if that was too hot. They said it was not a problem. 

The white smoke could have been steam, but it also could have been a little unburnt fuel. In any case, it doesn't sound like you have anything to worry about.

The engine doesn't have a mechanism that shuts it down when it overheats. In an extreme situation that would toast the bearings. The best thing to do if the engine starts to run hot, but still has some water coming out of the exhaust, is to throttle back and then go find the problem.

I usually reef the main or partially furl the jib when the boat starts to heel more than 15 degrees and/or I get too much weather helm and/or the passengers look scared. I'd guess that most of those things happen somewhere around 15 knots apparent wind.

JeffC
  ----- Original Message ----- 
  From: mike hunter 
  To: C320-List 
  Sent: Monday, May 14, 2007 2:31 PM
  Subject: [C320-list] Engine and Reefing Questions


  I'll start by saying I love this boat!  I have a couple of questions regarding engine temperature and what looked like steam coming out of the exhaust, but I'll get back to those in a bit.  
     
    Friday afternoon we fueled up and went for a little cruise around the San Diego bay, running the engine at different RPMs.  We found another 'sweet spot' at 2800 and kept it there for roughly an hour.  The engine stayed at its normal operating temperature of just a hair below 180 degrees.  
     
    Saturday morning we motor sailed to the mouth of the bay (~ 45 min.) and then proceeded to have a fantastic day of sailing.  It always feels so good to shut down the engine J.  That evening while coming in, we started the motor and motor sailed through the bay to the no wake zone then dropped the RPMs down to around 2000.  It was shortly after doing this my Wife noticed the temperature had risen to just a hair above 180 and there was what looked like steam coming out of the exhaust with the water.  She dropped the RPMs down to 1200 and I went below to check out the strainer.  The strainer had accumulated a little bit of debris but it was mostly clear.  When I came back up the temperature had dropped back down to normal and the 'steaming' had stopped.  It almost seemed like we sucked up something and then blew it out??? 
     
    My plan now is to clean the strainer, check the flow through the intake hose and inspect the water pump impeller - which I replaced 2 weeks ago.  
     
    Finally, my engine questions:
     
    -         What is considered 'hot' for a Yanmar 3GM30F?
    -         Does the engine shut down when it reaches a certain temperature to prevent damage?
    -         Am I on the right path or is there something else I should look at?
     
    I also have a more important sailing question.  The wind varied from 8 - 12 knots throughout the day and the boat sailed beautifully.  At what wind speed do most of you reef?  
     
    Thanks!
     
    Mike
    #637

         
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