My 4.3 manual states that the fault warning may be transmission fluid temperature too hot, engine oil pressure is too low, engine temperature is to hot, seawater pressure is to low or the transmission pressure is low. None of the fault warning indicated for the 4.3 TKS are contineous sounds. One...
You should change the gear oil in case there is water in the lower unit from a small leak in the gasket. The water/oil mixture could freeze and crack the lower unit. Mercury also recomends new engine oil due to the break down of the old oil which can cause pitting or corrosion. The due make a...
http://www.westmarine.com/webapp/wcs/stores/servlet/WestAdvisorView?langId=-1&storeId=11151&catalogId=10001&page=Winterizing-Checklist
Here is a great video about this subject