Re: [Amel Yacht Owners] RPMs and Temperature reading


Kevin Schmit
 

Use a handheld I/R (Infared Thermometer} to get independent temp readings.


On Sep 3, 2020, at 2:21 PM, Jose Venegas via groups.io <josegvenegas@...> wrote:

This was a very useful 3-year-old set of postings for me.  We just crossed from Grenada to Curaçao sailing for 48 hours with double spy and 18-22 knots of wind from the starboard stern.  As we got close to Bonaire on Sunday morning, the wind began to drop and, to make sure we got to Curaçao before the marina personnel left, I turned the engine on to motor sail when the wind dropped to 10 knots. We kept our 6 knots of speed, and everything was fine until the corner of my eye showed the temp gauge pegged at 250 F !!!.     The raw water stream from the exhaust U pipe was luck warm and I proceeded to make a quick change of thermostat for a brand new I had on board.  No luck, the temp went back to 250.  At his point, it became a matter of sailing with winds of 4 to 6 knots as we approached the entrance of the Punta Santa Barbara channel that leads into the Ceru Boca marina and tied up at a pier on the channel just before the sun disappeared from the horizon.  Next early morning I  took apart the thermostat housing again, cleaned the surfaces, and closed it again.  The test appeared successful for 10 minutes or more at 1500 RPM under load  (Temp 200 F)  but as we proceeded to motor up the few miles to the Marina, the temp went up again to 250 F for just a few seconds before it came back to 230 F.   Yesterday, I ran a new test, this time at 1800 RMP for more than 15 minutes and the temp when up and remained at 220.  I noticed that with the radiator cap opened the seem to be movement of the antifreeze and few gas bubbles would come out once in a while.  This, I thought, was meant that there was a flow of antifreeze but its temperature was bearly warm. 
After reading this set of posts, It seems possible that it could be either a faulty sensor, the gauge, or the cable to the gauge.  Any other thoughts/suggestions.  I am ordering a new thermostat to the US in the next few days.

Hope you are all well and sailing.
Jose Venegas
Ipanema SM2K   278

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