Yanmar 180 Coolant Temps

CaspersCruiser

Well-known member
Joined
May 11, 2016
Messages
921
Fluid Motion Model
R-27 Classic
Hull Identification Number
FMLT2709G112
Vessel Name
Cookie
MMSI Number
368203460
The parents of a colleague of mine have a Yanmar powered R27. I don’t think they are on Tugnuts. They intended to start the Great Loop this spring on the Chesapeake Bay near their home, but they encountered chronic overheating and engine problems on their newly purchased used boat. After major engine repairs and installation of a larger seacock and strainer that were finally finished a few days ago, they reported these coolant temperatures via their blog:

“Previously speeds over 2740 were impossible because of overheating.  Now we could run the engine at speeds above that -- as the engine was designed to do:
* We increased the throttle to 3200 -- it was running at 212 °F.
* We increased the throttle to 3400 and it was running at 214 °F
* We increased the throttle to 3600 and it was running at 217 °F
* We increased the throttle to 3800 Wide Open Throttle (the maximum the engine could possibly go) and it was running 219 °F”

Those temperatures are considerably higher than what I see in my Yanmar R27. My coolant temps are generally steady at 193°F. Their boat is a year or two later model than mine and maybe they have a different sensor or the temperature probe is placed in another location. What temperatures do you see on your Yanmar R27?
 
Keep in mind that the temperatures are computer generated. I used to get temperatures that you stated, but I also had a thermostat issue, long story different thread) and after that I am usually at 196 and at WOT up to 206. If I were them I would do a few things, A) make sure their thru hull is clear and not blocked, B) if they have not had the impeller checked and or changed do that C) I would do a Ridlyme descaling to make sure there is no blockage in the cooler. After that I would keep an eye on it and chalk it up to either a sensor or computer miscalculation. Replacing and even testing the sensor is nothing I would want to do unless absolutely necessary. You have to remove the exhaust manifold to get to it.
 
Good morning Caspers Cruser,
We are having the same temps that Ilusions is having.
At our normal cruse of seven to eight knots, about 70% percent load the temp is 196 & at WOT, wide open throtal the temp goes up to a max of 205. We have a 2012 Cutwater 26 with 750 hrs.
We have a 180 HP Yanmar engine.

Hope these two comparisons help with your question.
Best of luck,
Mike
M/V Elan
 
My 2011 Yanmar 150hp in a 25 foot boat runs at a steady 190 when cruising any where near displacement speed. It will climb to 196 at 3500 RPM. I've never run it above 3500 long enough to see any higher temps. My Yanmar manual suggests not running at 100% throttle for more than 10% operational time. It tops out about 3950 RPM.
 
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