[C320-list] Yanmar issue

[dprudden]

Just finished getting the 3gm30f ready fir the summer. I changed the oil,all filters, impeller, mixing elbow, belts, thermostat and flushed and changed the coolant. I had the heat exchanger ultrasonically cleaned and replaced the gaskets (yanmar has a new distributor and the bar gaskets on the exchanger now need to be cut to fit...the don't give you the right length anymore).
  So here's the question-I ran the engine today for 1/2 hour, using cold tap water to circulate for raw water. The engine wouldn't heat past 165 degrees.  Last year the temp was a steady 185. Would the maintenance I performed, especially the heat exchanger cleaning (which wasn't bad before the cleaning), cause her to run 20 degrees cooler? Could cold tap water just make it tough to get hot? 

Thanks for any suggestions.

David Prudden
#787