Hi,

My C36 has a Universal M35 with around 2.500 hours, never a problem but the the sherwwod sea water pump.  Today it was again leaking so I replaced by a refited one.  I also decided to replace the Thermostat, don't ask me why, the old one was working properly but, cause a found a new one on the tool box I did.

With the old one,  normal working temperature was achieved (160f) around 15' later after started. With a maximum temp at 180f, when at 2.800.-  

Well the problem is that after changing the sherwood pump at the thermostat, temperature does not go up than 100. I was testing at port, with gear engage at 1.500 rpm. And no way the temp goes up. I did a test by a short to verify temp se dear was ok, and it is. In fact it start to goes up so slowly...but no more that 100f after around 15,. Here in the Med we already have 18c.
The replaced thermostat was for some years in its plastic box inside the spare box.

Any idea what could be happing? Any test I can do? I understand thermostat opens when wax becomes liquid and remains close when cold, correct ?

Any idea will be most welcome.

Regards from the Mediterranean.