Regularly changing oils and lubricants in engines, transmissions and drive units is a necessary part of normal maintenance, but it is especially important in preparation for winter storage. Once used for even a short time, engine oil becomes contaminated with microscopic bits of metal produced by normal wear and by the corrosive byproducts of combustion. Leaving used oil in an engine for an extended storage period can allow the pollutants to settle into a hard-to-remove sludge and let the acids damage sensitive surfaces within the power plant
The gear lubricant in outboard and sterndrive lower units not only collects abrasive metal bits but is susceptible to contamination by water, as well. Changing it is a must.
There are several things you can do to make oil and filter changes easier and more effective.
- Begin by loosening spin-on oil and fuel filters mounted directly to the engine while the engine is still cool. Back them off just to the point where they can be removed without a wrench but not so far as to allow leaking. This makes them much easier to deal with after the engine is warmed.
- Run the engine long enough to raise the temperature of the oil. This makes the oil easier to pump or drain, and ensures that contaminants are suspended in the oil and will come out with it, rather than remaining settled in the oil reservoir. After shutting off the engine, wait for its oil to drain back down into the pan or reservoir to ensure that the maximum amount of old oil is removed.
- For spin-on filters that use replaceable cartridges, wipe any residue from the bottom of the canister so that it doesn't end up in the new filter.
- After refilling with new oil, run the engine only long enough to check for leaks, if possible, to avoid contaminating the new oil.