Winterizing Your Boat

Winterizing your boat is a very important practice that prevents cracks and corrosion on your engine and outdrive(lower unit) protecting your vessel from the elements of cold weather. Whether you have it done by a professional or you do it yourself, you don't want to end up with a horror story of your own with expensive repairs like we did in Boating Horror Story 4.

Usually we wait until the last minute because we always like to go out on the water just one more time! Just make sure the weather doesn't freeze before you get to the winterization process. There are many ways to winterize a boat and many opinions on what to do and how to do it. This is how we do it, broken down into 3 separate areas of winterizing covering 1. Fuel, filters, additives, and oils 2. Administering antifreeze and 3. Loading up grease fittings. Follow this up with removing your battery(s) and you'll be all set until spring, when you can come back and follow our Summer-izing guide to get ready for warm weather again!  Read below, the underlined items are in the pictures nearby-click on those pictures to enlarge.

Fuel, Filters, Additives, and Oils

For this process you will need:

  • Marine Formulated Sta-Bil
  • 2 Quarts of Gear Lubricant
  • Quart Pump
  • Oil Filter
  • 5 Quarts of Motor Oil
  • Fuel/Water Separator Filter
  • Flat-head Screwdriver
  • "Earmuffs"
  • Garden Hose
  • Drain Pan
  • a few rags
  • Vacuum Canister-optional

Sta-Bil Marine Formula

1. Get a few bottles of marine formulated "Sta-bil" additive for your fuel tank. You can figure how much you need by following the dosage instructions on the back of the bottle. Typically you'll put in 1 ounce of additive for every 5 gallons of fuel. Once you have that figured add the "Sta-bil" to your fuel tank.

2. Now fill your tank the rest of the way with fuel. The reason for filling it as much as possible is that, just like in a car, the more space your fuel takes up in the tank, the less condensation builds up diluting the fuel, therefore making your engine happier.

Fluid Extractor Pump

3. Drain oil or use a Fluid Extractor Pump to remove all of the oil and/or any contaminants, including water.

4. Remove and replace the oil filter.

5. Add new oil until it reaches the proper level.

Fuel Water Separator

6. Remove and replace fuel/water separator filter.

Outdrive Drain Plug
Outdrive Vent Plug

7. Remove Drain plug, then Vent plug in order to drain lower unit fluid into a drip pan. We do this in case there is water inside the outdrive(lower unit) and to check for any metal shavings and other debris on magnetic drain plug.

8. Add new fluid to lower unit-for this step you will need a Quart Pump and 2 quarts of manufacturer specified gear lubricant, which can be acquired from a local boat shop or online. Usually Quart Pumps cost around $15 each.

Quart Pump

Keeping the drip pan in place, attach the Quart Pump to a quart of gear lubricant oil and attach the other end of the Quart Pump to the drain port. Pump the gear lube in through lower drain port until it comes out the vent hole. This will use about 2 quarts.

Once the oil starts to come out of the vent hole, stop pumping and insert the vent plug. Remove hose from drain port and insert magnetic drain plug.

Marine Motor Flushers

9. After all new fluids are changed and topped off, it is time to grab the marine motor flushers or "earmuffs". Attach garden hose to "ears" and slide "ears" over the water intake. Turn garden hose water on and start the boat engine. This will ensure the inside of the engine and lower unit has a coat of fresh oil and allow the fuel treatment to enter the entire fuel system. Run the engine with the water flowing for about 5 to 10 minutes or until the engine warms up. Once you are done with that, this process is finished and you can clean up to get ready for the next process.

Administering Antifreeze

This is where some people have their own opinions. When doing their own winterizing, some people prefer to take out all of the drain plugs on the engine to remove water, this is something I disagree with, 2 reasons I disagree are...

  • It is unnecessary to remove all drain plugs and...
  • I have seen and heard of people not remembering to put all drain plugs back in when they get finished with winterizing. Come spring time they take their first voyage out on the water and after they have departed the dock and are cruisin' around, they realize that water is pumping into the engine compartment at an alarming rate. Since this is the product of something they did perhaps 6 to 8 months ago, it can take some time and inspection before realizing what is happening. Bilge pumps are great, but some are not meant to keep up with this much water being brought in. If you do find yourself pumping in water, just remember to stay calm, turn off the engine and let the bilge pump do it's job. That's the great thing about boaters, if your out far enough that you need a tow, there's usually someone around to help you back to the dock if needed.

These steps are how I get all of the water out of the engine without removing every drain plug.

For this process you will need:

  • a few gallons of full strength Antifreeze(not 50/50)
  • 2 large buckets
  • a flat-head screwdriver

1. In order to catch anti-freeze, put 1 bucket under exhaust and the other bucket under the lower unit. The second bucket should be rather large so that the outdrive can be lowered into this bucket.

Engine Coolant Hoses

2. Disconnect the "higher" end of each of the coolant hoses and drain standing water into engine compartment-don't worry it will drain out through the drain hole in the bottom rear of the boat.

3. Use a funnel to pour full strength antifreeze into each hose that you just disconnected. You will pour the antifreeze in each hose until either you can't pour anymore, or it comes out of the exhaust.

4. Reconnect hoses.

Water Pump Inlet

5. Lower outdrive into the bucket below and fill the bucket with full strength antifreeze above water pump inlet, which is about a foot from the bottom of the lower unit and looks similar to a vent.

6. Start engine and let it run until antifreeze is continually coming out of exhaust. Being sure to keep antifreeze level in bucket above the water pump inlet.

7. Turn off engine, raise outdrive/lower unit, remove buckets of antifreeze and clean up.

Loading Up Grease Fittings

Now it is time to grease all the fittings. Each boat may be a little different, but most have a few on the lower unit, a few towards the rear of the engine compartment, on the steering and coupler, and last but not least, wheel bearings on the trailer. If you have "Bearing Buddies" it makes life a little easier. They are spring loaded to keep pushing grease into the bearings so water can't get to them. If you don't have "Bearing Buddies" and you have to do it the old fashioned way, look below for those instructions.

For this process you will need:

  • a grease gun with grease in it
  • a couple rags

1. On the outdrive there are 2 grease fittings for the Trim Sending Unit (one on each side of the outdrive) and one for the Gimble Bearing. Attach grease gun to fitting, pump in grease until clean grease squishes out of the side of Trim Sending Unit and the Gimble Bearing will get about 5 or 6 pumps of grease. Wipe away any excess grease so not to get dirt build up.

Bearing Buddy

2. Next will be the Bearing Buddies. Remove the dust cover, and wipe out old grease on each one. Attach grease gun and pump grease in until spring is compressed, you will see the spring movement. Wipe away any excess grease so not to get dirt build up.

3. Inside the engine compartment, towards stern, is the steering grease fitting and coupler grease fitting. Attach grease gun to each fitting and pump grease in until new grease squishes out. Wipe away any excess grease so not to get dirt build up.

Last but not least, you'll want to remove your battery or batteries as the case may be. This way you won't have to shell out extra cash at the beginning of the next season for new ones. We always unhook ours and store them on a wooden shelf, checking them every once and a while for charge, and when need be hooking them up to the battery charger to keep them good. When spring-time comes, simply put them back in the boat, hook 'em up, and your all set.

That's all there is to it. You are done winterizing.

No Bearing Buddies on Trailer Wheels?
No Problem

For this process you will need

  • a jack
  • jack stand
  • lug nut wrench
  • axle grease
  • rags

1. Loosen lug nuts(do not remove).

2. Raise the wheel off the ground and put the jack stand under the axle. The jack stand is a back-up in case the jack gives out.

3. Remove lug nuts, wheel, cotter pin, axle nut, washer, bearing, hub, bearing.

4. Clean off as much of the old grease as you can from the bearing, hub and the spindle.

5. Apply new grease on bearings, pushing it through all rollers. Apply a small coat to spindle and hub.

6. Put the inner bearing back on the spindle, then the hub, then the outer bearing. Put the washer and axle nut back on.

7. Tighten axle nut on to spindle with force, then loosen axle nut just a hair in order to align hole on spindle with axle nut, and insert cotter pin.

tip: Always try to put cotter pin in hole from the top. That way if, for some unknown reason, the part of the cotter pin breaks, it won't fall out.

8. Reinstall wheel and lug nuts-tighten.

Repeat on each wheel.

Go Back to Boat Maintenance Main Page

Let yourself be open and life will be easier.  A spoon of salt in a glass of water makes the water undrinkable.  A spoon of salt in a lake is almost unnoticed.


"For whatever we lose
(like a you or a me),
It's always our self
we find in the sea."

-E.E. Cummings

Pure water is the world's first and foremost medicine.

-Slovakian Proverb

A lake is the landscape's most beautiful and expressive feature.  It is Earth's eye; looking into which, the beholder measures the depth of his own nature.

-Henry David Thoreau

"Take your shoes off,"
purred the ocean waves.

-Dr. SunWolf