Winterize My Boat?

Holiday Harbor Service Center

As a full service marine operator at Holiday Harbor Marina,  you would be surprised how many times I get a look of confusion when I ask a tenant if they have winterized there boat.  Of course these are new boat owners as anyone that owned one of over a year would now know one way or another.  Hopefully they learned the easy way and didn’t have to buy a new block.  We never take it for granted that not every boater is well informed or listened while the seller was talking instead of dreaming of how much fun the summer is going to be.  We like to remind every tenant that it’s getting time to prep your investment for a winters nap.

This article is written to give new boaters a basic understanding of what is involved in a proper winterization and not as a technical article or a How To article.   Myself and most anyone in the business will recommend that you take it to a reputable mechanic or marina and leave all the liability with them.  If you take it to a mechanic which is HIGHLY SUGGESTED, you will want to see an itemized list of all the services rendered, especially if you take it to the lowest advertised price in town.  A poor winterization can be as simple as draining the block to keep it from freezing and is not what you are looking for.

I will break the information down into four basic areas of winterization.  Outboard Engines,  Inboard/Sterndrive Open Loop,  Inboard/Sterndrive closed loop and General Boat Winterization guidelines for all boats.

*Outboard Engines:  

Holiday Harbor Marina & Boat Sales

The main area of concern is with the fuel system, cylinders, oil and prop.

First thing you will want to do is get the fuel system full of treated fuel.  This is done by adding a Stabilizing agent to your fuel tank and running the engine for about ten minutes to ensure it makes it thru all the lines.  Once the ten minutes is up you will want to spray an engine tuner thru the air intakes.  This will help to “clean out the system of any contaminates, mainly carbon deposits”.  Next step is to use a “fogging” spray which will coat internal surfaces and protect them from oxidizing.  You will also want to pull the plugs and spray each cylinder down with the same “fogging” spray.  Change the Gear lube, if it has water in it it could possibly freeze and crack.  If possible store the motor down so that water can not pool up in your exhaust port and freeze.   If you have to leave the motor up then place a plastic bag around the prop.

*Inboard/Stern Drive Open Loop

Holiday Harbor Marina & Boat Sales

First off let’s discuss what an open loop or Raw Water Cooling system is.  In an open loop system “Raw Water” is picked up from the water you are boating in thru the engine block and returned back into the water.  Most inland boats designed and sold to be used inland will have this type of cooling system.

The main concerns in winterizing this type of engine is to make sure no water is left in the block to freeze and crack, but before we get to that you will want to run stabilized fuel thru the system.    Next, the engine block and manifolds will have drain plugs that need to be removed or opened and drained of water.  You can stop at this point, but you should fill the system up with a marine engine coolant to make sure no raw water is hiding in some nook that can cause freeze damage.  You will also want to fog the engine similar to the procedures outlined on the out board motor.  If it is a stern drive you will want to change the oil in the drive.

*Inboard/Sterndrive closed loop

In this style cooling system, water is picked up and circulated thru a heat exchanger to is similar to your radiator in your car.  Once again first thing is to run stabilized fuel thru the system.  Next step will be to check the coolant level on the engine side of the exchanger and then drain the water from the intake side. The rest of the steps are the same as that of a Open Loop System.

*General Boat Winterization Guidelines

Treat the Fuel in your tanks and top it off to 95%.   Keeping the tank full will reduce the condensation that can be absorbed by ethanol and greatly reduce the chance of phase separation.  Make sure any fresh water lines “sinks etc”  are drained.  Clean all vinyl and coat with a good protectorate.   I usually don’t recommend specific products Brands, but one that stands so far above the rest her Aerospace Protectant 303.  Cover your boat or better yet have it shrink wrapped by a marine professional.  You will want to add some absorbent packets to the inside to help eliminate or reduce mildew growth.   If you store the boat away from your house,  make a few trips out to check and see everything is ok.   If some one has broken into your boat or damaged the trailer etc. you will be the first one to notice.  Most storage yards have so many boats it’s nearly impossible to remember everyone and just how it was covered or if the trailer light was damaged.  The sooner that is reported the better chances of catching the culprit.

Another Disclaimer:  Think of this as a list of ingredients not a complete recipe,  by no means should you rely on this information alone to winterize your engine.  You will need an engine specific manual and boat specific manuals to make sure you follow all the procedures.  I suggest you shop around reputable shops, find out what is included or tell them what you want and have it done by a professional.  Even our professional shop has missed a hot water wash down before and we were obligated to fix it.  The customer never mentioned that he had one, but as a respectable shop the tech should have looked to make sure.

Eric Williams

Holiday Boat  Service & Sales
5989 Groovers Landing Acworth, GA 30102
Phone:  770-974-2575

Holiday Harbor Marina and Boat Sales