[C320-list] Engine water temp problem

[Onat Dogruer]

On a side note, I just replaced the 18 year-old Johnson water pump (with same model Johnson pump) on our Yanmar and the temperature is not going above 160. It used to hover around 170F. I wonder if they improved somehow the efficiency. 
-OnatKittiwake #546, 1998

      From: Allan S Field <allan.field at verizon.net>
 To: C320-List at Catalina320.com 
 Sent: Thursday, April 6, 2017 2:20 PM
 Subject: Re: [C320-list] Engine water temp problem
   
Our boat was about 10 years old when the temp sender unit failed.  A
replacement was ordered from Yanmar for about $20 US 7 years ago and
installed in about 10 minutes.  Problem fixed.

Allan S. Field
Sea Shadow - C387, #103
Columbia, MD

-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Graeme Clark
Sent: Thursday, April 6, 2017 1:14 PM
To: C320-List at Catalina320.com
Subject: [C320-list] Engine water temp problem

First time I run the engine this year the water temp gauge goes off the
clock!
I therefore bought a point and shoot laser thermometer and sure enough the
engine temp ( measured where the sensor is and also at fuel injector points)
is around 170f whereas gauge is showing 280-290f

So it's the sensor or the gauge. How do I test the sensor.  There is only a
single terminal so I'm guessing the resistance changes with temp. Does
anyone know what resistance should be at say, 170f ?

Or is there a simple way to test gauge

I did have the instrument panel out this winter to repair the lid so it
could be a dodgy connection I guess. I'll check everything again but any
more info would be handy as I'm stuck on boat with limited internet access!

Graeme
#366, 1996 running Yanmar 3GM30F


Sent from mobile: please excuse typos etc.!