Oil through cooling system (Hypothetical question)
 

Quick question for anyone that may have some input on the subject....what would happen to the water cooling system of an outboard if it is run through an oil slick?

Water pump impellers will break down faster from the heavy oil. The biggest problem is the heavy oil will block up water jackets, passes around cyclinder heads, thermostats, etc.. It could be a very big problem

If it coats the inside of the engine, the water won't make a good heat exchange either. It will insulate the metal from the water a little bit.

What about runnin some degreaser through it. I use simple green to degrease almost everything it probably would clean out your water passeges also.