Inboard or Outboard? Freshwater cooled Inboard should be winterized. If raw water cooled maybe drain the manifolds by pulling the drain plugs. Outboards? I leave mine out all winter, just leave it down until all the water drains out after flushing and running. Might be easier just to leave boat on the trailer at night. A heat source next to the inboard would be nice.
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God grant me the serenity to accept the size of fish I catch, the courage not to lie about it, and the wisdom to know that no one would believe me anyways.