As a newbie, one of the mantras impressed upon me by all and sundry is to check that there is water
coming from the exhaust
when the motor
is first started.
I have duly done this and have had several anxious moments when finding that it does not appear to be thus.
My boat has an MD11C fitted and looking at the workshop manual
flow diagram seems to suggest that the only outlet for the water is from the thermostat housing. This would suggest that there would only be water passing into the exhaust
when the engine
has reached minimum thermostat opening temperature. That in turn suggests that no water goes through the gearbox
until the engine
One of my friendly locals in the marina thought that there must be a bypass but I can't see one in the diagram or indeed on the engine itself.
I have seen water coming out of the exhaust when the engine is warm...
In addition to this worry is that the temperature gauge moves up and down when the boat is motoring along. It never goes too hot or too cold but seems to cycle around a point which would be at the top of the gauge. I could rationalise this as the thermostat opening when the motor
gets warm and then closing again as the flow of cold sea water replaces the hot stuff but I'm not 100% sure...
Is this correct? Or is it a sign that the thermostat is on its way out and should be replaced?