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How to Winterize Your Engines


Winterization Made Simpler

These eight tips can make it less painful to put your boat away for a season.

It’s that time again when those of us who live where the water gets cold and hard must think about putting our toys away for a while. It’s bad enough that our fun season is coming to an end but on top of that we have to go through all the hassle of winter layup.

But really, winter layup, at least as far as it relates to your engine and drivetrain, is really quite simple, and just about anyone who can fog a mirror can do it themselves. It mainly comes down to oil and batteries, and if you know a few tips, the job can be quick and easy. 

The oil part is simple: Change your engine oil and filters. But there are a few tips that will ensure you do the job —. Drain the oil when the engine is warm so you get the maximum amount of dirty oil out of the engine. The oil does not need to be hot; warm does just fine. Many of us are lucky enough to have engines equipped with electric oil-change systems, and if you do here’s another tip. Run the pump until it’s obviously sucking air, then wait 15 minutes and hit the pump one more time. You’ll be surprised how much more oil you’ll get out.

Obviously you need to also change all filters; doing so can be a messy job that ends up spilling dirty oil into your bilges. Next time put the filter in a plastic bag before you begin to unscrew it. That way any spillage ends up in the bag, not in the boat.

I always wipe the old oil off the filter mounting surfaces although frankly I’m not sure what the benefit is beyond making me feel good. I’m more certain that it’s worth the extra effort to fill the new filter with oil before installing it because that will preclude a momentary delay in the oil supply when you restart. (If you’ve got an inverted oil filter you obviously cannot do this.) The same is true when changing your fuel filter or separator. 

And despite what you may have heard on the dock, the best time to change oil is before winter layup. I recently received two e-mails arguing that it’s better to change oil in the spring so it doesn’t “age” over the winter. Well, oil doesn’t deteriorate in such a short time, and besides, if you leave dirty oil in your engine over the winter, you’ll subject its innards to all the acids and other nasty stuff it produced during the season. Don’t delay; change oil now, and after you’ve done it, run the engine for a minute or two to circulate clean oil throughout the engine.

There really isn’t much controversy about how to deal with engine oil at layup. Such is not the case with batteries. Traditionalists say you should remove all batteries and take them to a relatively warm environment where you place them on a non-conducting, dry surface and attach them to a trickle charger. All this is to minimize the deterioration that comes when a battery naturally discharges when idle. 

I’m not about to argue with a procedure that has proven itself with generations of boaters. At the very least, it will do no harm. But it’s not only a lot of trouble, it may not be necessary. Gel-cell and AGM batteries typically do not self-discharge as quickly as the old wet-cell versions, and besides, simply connecting a battery—any battery—to a trickle charger could result in overcharging. And don’t forget, there’s no need to put batteries in a nice, warm spot as a fully or nearly charged battery will not freeze.

I believe it’s perfectly acceptable to leave your batteries in the boat provided you take a couple of precautions. First, shut off the battery switches so that the state of charge won’t be affected by some errant load—like that light in the hanging closet that sometimes fails to go off when the door’s shut. Second, if your boat will have access to electricity over the winter, invest in a battery conditioner or battery minder, which is not the same as trickle charger. There are many models on the market. For the past seven years I’ve relied on a couple of units by Charge Master and they’ve worked great. They purport not only to keep the battery charged but also prevent sulfation and other deterioration. I paid $40 for each, and as I have not had a single battery failure since I started using them, I consider that a bargain. 

Won’t have access to 120 volts? I recently got an e-mail from a reader who rigged up two conditioners to a small solar panel. He says it worked like a charm as long as he remembered to stop by and brush the snow off the collectors. Of course if you’ve humped all your batteries down to your basement or if you live in Florida, you won’t have to bother with that.

This article originally appeared in the October 2015 issue of Power & Motoryacht magazine.