An oil change is simply that- Change the engine oil and filter. This may or may not include the generator. An oil change does not include items like fuel filters, heat exchanger zincs or checking belts and hoses.
It does not include the often overlooked and underrated impeller the heart and life-blood of your cooling system. It never includes a gear oil service.
An annual service includes all of these things.
Did you know that after only 100 hours of running your engines (mains and generator) your fuel filters can plug up from asphaltine or debris in your fuel tank?
Did you know that fuel sitting in a fuel filter breaks down and can plug a filter without actually running the engine? This is caused from the asphaltine dropping out of your fuel and the fuel going bad.
A lot of boat owners do not know what an impeller is. One boat owner told me last week the impeller has never been changed in the 10 years he has owned his boat and wanted an estimate for the service.
An impeller is a rubber piece that pumps saltwater through the seawater side of your cooling system. Instead of having air like in your car to cool the coolant, your boat has seawater to cool the coolant. The impeller is the one and only device to push this cooling seawater through your engine and keep it from overheating.
If left alone it wears, rots or takes a set causing low or minimal seawater flow. My philosophy is when in doubt change it out!!! The consequences of not changing it are possible major internal engine damages. The impeller should be changed every two years or two hundred hours regardless of what your buddy tells you.
The transmission is also often overlooked. Change the oil in it every other year or better yet every time you are due for an impeller change, change the marine gear oil (transmission).
GET AN ANNUAL SERVICE NOT AN OIL CHANGE