In Reply to: Synthetic Oil Change posted by Bruce Buchy on 10/07/01 at 11:16 AM:
When I winterize my boat, I look for any sign of water in the oil before I change it. To do this, run the engine until warm, take a few drops from the dip stick and place them on a hot piece of foil (I use the barbecue). If the oil crackles when it hits the hot foil, you have water. No crackle, no water. Dirt ingestion on boats is minimal - therefore the main concern is water. If no water is present, no need to change the oil. Change the filter and top up. For the outdrive run the same crackle test to determine if you have water in the oil. If not, keep the oil for two or three seasons.
Extended oil drain intervals, that are well managed, benefit your wallet and the environment.
The synthetic oil in my twin 302 inboards is on the fourth season. No water yet.