The gauge on my 2015 Yanmar 3YM20 in a Catalina 315 shoots immediately up to 240 degree F. The engine seems fine and I now suspect the sender unit to be faulty. the Yanmar manual only describew a High temp alarm switch (located above/to the right of the Thermostat housing), but not the tempersture gauge sender, which sits to the left of the thermostat housing under two cooling hoses- blue wire on my engine) . Is this a Catalina thing? Does anyone know the paretr number or the manufacturer of the sender unit? I cannot find anything on Yanmar.
Cooling water temperatture gauges on Yanmar 3YM20
- Thread starter Mahi
- Start date
If the gauge always reads full scale (240F) then that would indicate that there is a short in the sense wire to ground. This could be a bad sender that has an internal short, or a short in the wiring harness.
If on the other hand, the gauge reads normally and only sometimes goes to full scale, then you have an intermittent and it will be much harder to locate.
Attached is a document that describes how to test a gauge or a sender. It is written by Teleflex, but will apply to all brands of USA standard gauges.
If your over-heat alarm is not active, you are most likely not overheating. You can easily confirm this with an IR thermometer.
If on the other hand, the gauge reads normally and only sometimes goes to full scale, then you have an intermittent and it will be much harder to locate.
Attached is a document that describes how to test a gauge or a sender. It is written by Teleflex, but will apply to all brands of USA standard gauges.
If your over-heat alarm is not active, you are most likely not overheating. You can easily confirm this with an IR thermometer.
