Marine Parts & Accessories

Marine Parts, Supplies & Accessories

Winterization Tips for your Mercruiser Engines.

Taking time to winterize your boat correctly will insure that
your boat is ready for dependable operation when Spring comes along.

Winterization should start with a good tune-up!

Haul your boat and make sure your bottom and drives are cleaned of
any barnacle or grass growth. The sooner you clean or pressure clean
the boat after haul, the easier it will be.
Run your engines on flush-muffs or a similar fresh water flushing system
with good, clean fresh water for about 15 minutes each engine.

Note all gauge readings for proper operations and listen to the engine
for any weird noises which may be an indication of existing problems.

Now is the time to address any mechanical problems that you might suspect.

For example, if you here a slight tapping noise and the engine really doesn't idle
that great but you ignore this problem till spring, your engine may seize up from
rusty water that has leaked into the cylinders!

The above example is actually VERY COMMON.

After you have flushed the engines on the hose it's a good idea
to run some antifreeze through the system.
PLEASE observe any environmental laws and safety concerns that may
pertain to the coolant/antifreeze products that you are using.

Please note. The next step involves sucking an antifreeze mixture
from a bucket using the suction of the water pump in the drive unit.
If your water pump is not in perfect condition then the pump
might not be able to draw the water from the bucket.
This could cause an engine over heat condition which could lead to
extensive (and expensive) damage.

Take careful note if the hose is sucking from the bucket right away.
If you get no suction then you have a problem with the hose, the flushett,
or the water pump.

Get a 5 gallon bucket and mix up a 50:50 batch of antifreeze and water.
It's good to use a short (6 foot long) garden hose that has the
engine flushett at one end.
Make sure the bucket end of the hose stays at the bottom of the bucket
so that it doesn't suck air!

Note: The next step can be dangerous and it is recommended that
an experienced Mercruiser mechanic perform the fogging operation as removal
of the flame arrestor is necessary which can lead to burning, damage,
injury and death. The flame arrestor on a boat is different from a cars
air filter. A boats flame arrestor prevents backfires from exploding dangerous
gases which can accumulate in the boats bilge.
NEVER run a boat without an installed flame arrestor unless care is taken to
prevent such explosions and fire fighting tools are close by and in good condition
in case the need should arise to extinguish a gas or oil fire.

Sorry about that lecture. It was important.

Following and knowing about the warnings above, remove the flame
arrestor from the carb and have a can of fogging oil close by.
Fogging oil now comes in spray cans. Mercruiser's fogging oil is
called Storage Seal and works great. You can also use a quart can
of Marvel Mystery Oil if you like.

It's a good idea to have a friend on the outside of the boat watching
the garden hose and monitoring the fluid level in the bucket.

This all has to happen smoothly!

NEVER run the engine without a water supply! Not even for 10 seconds!

Start the engine and let idle while observing the fluid level in the bucket.
Before the bucket is empty, start to fog the engine but don't let it stall.

Just before all the fluid is sucked out of the bucket, stall the
engine by fogging at a faster rate.

Once the engine has stalled, stop fogging.

Reinstall the flame arrestor and plastic cover if supplied.

Some people prefer to leave the engine as is from this point.
We recommend that the block and manifolds be drained.

To drain the block, you will have to remove some type of block plug
or open some type of petcock valve.
Mercruiser has used a few different types of petcocks and/or plugs.

Some look like brass wingnuts with a drainhole in the center.
Some are as simple as a brass plug.
In either case, they will be located on the side of the engine block
usually just behind where the motor braces bolt to the block.

These drains can be very difficult to remove some times.
Also, when removed, they might be plugged with rust and wont drain.

If the passage is plugged then take a thin screwdriver and rheem the hole clean.

Next you will need to drain the exhaust manifolds.
The bottom of the manifolds will sometimes have petcocks or brass plugs.
Sometimes the manifolds wont have drain plugs and in this case
you simply need to remove the water hose from the bottom to drain it.

The large water hose on the front of the engine should also be removed
as it will puddle water even after the block is drained.

Get some good anticorrosion spray such as LPS#2 or Mercury's
Corrosion Guard and spray the entire engine with a good coat
while trying to avoid the plugwires and belts.

Make sure your bilge is clean as well as the rest of the boat.

Remove the battery, charge it up and store it in a well ventilated
dry and safe area so it's not sitting on the ground.

Remove the drain plug so melted snow won't sink your boat on the trailer!

Remove the speedometer tube from the back of the speedometer and
blow through the tube to expel any water in it.

Change your outdrive lube with whatever the factory recommends.
If you had noticed ANY water in the old drive oil then take the
outdrive in for service right away. Don't wait or your repair bill
will be extremely higher due to the rusting of expensive parts.

Remove the prop and grease the propshaft.

Grease the transom zirt fittings and steering system.

Store the drive in the down position to prevent water from freezing
in front of the prop and cracking your case. Also, it prevents the
U-Joint bellows from getting distorted.

Your local marine store should have additives for your fresh water system.

Drain the pipes and hoses. Also empty any sea-stainers you inboarders might have.

Don't forget to winterize your generator set too!

Did I forget anything?

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