Many boat owners don’t really know or understand too much about boat engine maintenance. Most boat owners place too much emphasis on changing the oil, not realizing that the majority of boat engine damage is the result of failure to maintain the cooling system. Contrary to popular belief, a boat engine cooling system is different from a car. Unlike cars, boats use the water that they are floating on to cool the engine. Therefore, if you’re riding around in polluted water, more than likely, your engine is getting the worst of it. For this reason, it’s recommended to have good filters (aka: sea strainers). This is not a place to be frugal; find out what type of water your boat usually sits in. If your boat is usually docked or riding through salt water, it will ruin your engine over time which is why you need to make sure that your water pumps are inspected regularly.
If you have a closed cooling system on your boat (aka: fresh water cooling), you need to be wary of crud building up. The build up will act like an insulator, gradually slowing down the cooling system on the boat. When you are pouring coolant into your engine, make sure that you aren’t pouring too much. As we all know, too much of anything is usually a bad thing. And actually, having too much coolant will cause unwanted crud to build up. Also, make sure you read the manual for instructions on how to properly pour in the coolant (because there is a specific process for doing it).