Generally, equipment managers "winterize"
equipment to increase or maintain performance in winter or prevent
problems after long periods of winter storage. However, this is
not only necessary in the winter. Many engines that operate in
areas that see no winter at all still need this type of service.
Therefore, I like to refer to this as seasonal service,
Some people perform seasonal
maintenance simply because the owners manual tells them
to, without understanding that good practical reasons exists to
perform this maintenance. It helps the engine perform better and
last longer. Seasonal maintenance also reduces down time and repair
bills. Whenever an engine does not run for an extended time (6
to 8 weeks or more), regardless of climate, you should perform
Step1: Choose a suitable
The storage location you choose
for your equipment is important. If you store the engine out of
direct sunlight, your results will be far better. Sunlight causes
problems because it warms up metal parts, which then cool down
when the sun no longer strikes the equipment. This causes water
condensation to form. In a semi-sealed area such as a carburetor
fuel bowl or a crankcase, this condensation can accumulate. When
this happens in cold climates, ice can form in these areas. The
result may be broken parts and big repair bills.
However, even in warm climates
this is still a problem because water in the fuel system will
cause an engine to run roughly or quit. Plus, if you allow water
to remain in the fuel bowl for an extended period, it can cause
oxides to form on the aluminum parts. These white particles often
dislodge and plug vital parts such as the fuel passages. I have
even found such severe pitting that I had to replace the entire
carburetor because some parts had completely dissolved.
Water in the crankcase can
blend with the oil or cling to unprotected metal, causing rust
to form on machined parts. Sunlight can also cause plastic and
rubber parts-such as hoses and rubber manifolds-to fail from prolonged
intense exposure. Good storage sites are cool and dark (shaded).
In such sites, the temperature is less likely to vary enough to
cause condensation to form.
Step 2: Prepare the
Cooler temperatures also minimize
evaporation of the fuel during storage. Usually a smaller volume
of fuel evaporates more quickly than a large volume of fuel. For
this reason, I suggest that you drain your carburetor fuel bowls,
but keep the fuel tank as full as you can. Another reason to keep
the fuel tank full is to keep the unpainted surfaces of the tank
coated with fuel. This will keep rust from forming on exposed
areas. One last reason to keep fuel tanks full is that air temperature
changes more quickly than liquid temperatures. Thus, the temperature
swings wont be as great with a full tank, and you wont
end up with nearly as much condensation.
If your equipment has a plastic
fuel tank, dont think that you are in the clear. The tank
may not rust, but you still have to deal with condensation. Therefore,
if the size and situation allows, drain the plastic tank as well
as the carburetor. Then you should not have any metal parts that
This is a good place for a
word of caution about two-stroke engines that use a diaphragm-type
carburetor. If you drain the fuel from these engines, you may
cause diaphragms to crack or harden. In this case, I feel its
wise to keep the fuel tank full and to use a chemical fuel additive
designed for storage. In addition, these small carburetors are
especially susceptible to varnish formation. This is another reason
to use chemical fuel additives instead of draining the system.
Step 3: Repairing
any fuel-system problems after storage
If you stored your equipment
properly, you will probably have few repairs to make when you
bring it back into service. However, if you neglected to prepare
your equipment properly for storage, you may need to perform some
* Four-stroke engines.
With four-stroke engines, the storage damage you are most likely
to experience is gummy carburetors or dirt. The dirt is usually
a result of the varnish (the residue left behind after fuel has
evaporated) remaining in the fuel bowls. If you catch it early
enough, it may be soft and gummy. However, if you leave it for
an extended time, it turns to hard crystals. These crystals can
dislodge and float around in the fuel bowl when you add new fuel.
They then can plug the small orifices that control the fuel flow
to the motor.
To remove varnish in the early
stages is easy. Simply spray some choke-and-carburetor cleaner
in the problem areas, and it will rinse away. Another trick is
to use compressed air for the problem areas and tight passages.
The problem becomes more difficult the longer you leave it unattended.
If the varnish is hard, you first must use dip-type carburetor
cleaner. You usually can find this type of cleaner at automotive-supply
Dip-type cleaner is highly
caustic, so be careful in how you handle this material. Read
the label for soak times and proper clean up. Most carburetor
part dips can dissolve small rubber parts, so you must completely
dismantle the entire carburetor and remove all rubber pieces before
using the dip. Take the carburetor completely apart so the chemical
can reach all parts and passages. In many cases, it may be necessary
to soak the carburetor two, three or more times.
Be sure to follow the labels
time schedule for keeping the carburetor in the solvent because
it can destroy the metal parts if you leave them in the dip for
too long. If the dip needs additional time to remove deposits
completely, remove and clean the parts and then repeat the process
rather than exceed the recommended time limits in a single dip.
I have seen some cases where aluminum parts were pitted so badly
from excessive dip times that they required replacement.
If you find that your problem
areas are in the small air bleeds and vents, use a small parts-tag
wire or a torch tip cleaner. However, use caution with
this method because it is easy to enlarge the holes if you are
* Two-stroke engines.
You can use many of the same methods for two-stroke engines. However,
be aware that you may find more rubber parts and diaphragms that
the solvents can damage. Fortunately, the oil/gas mixture in two-stroke
engines helps keep the varnish in a softer, gummier stage for
a longer time.
Step 4: Clean and
repair fuel tanks if needed
You can clean fuel tanks in
much the same way as carburetors-you just dont have as many
parts with which to deal. The first step in cleaning a fuel tank
is to drain it to see what kind of problem you may have.
If the problem is rust, pour
a small pack of BBs in the tank with some parts-washing solution
and shake it vigorously. This loosens the large, scaly pieces
of rust. After you have shaken them around, pour the BBs into
a paint strainer (to save them for use later). Now flush the tank
several times with clean parts-washing solvent to remove any remaining
If you caught the problem
early, you might not have to do anything more than this. However,
if you find pitting or small holes in the tank, you will need
to seal the inside of the tank with a liquid seal made specifically
for gas tanks. Avoid other types of sealers because the fuel
might dissolve them, causing more problems farther downstream
(in the carburetor).
Just because you have a plastic
fuel tank on your equipment, you are not out of danger. Dried
fuel can still cause a varnish-type material to form in the tank,
and it can plug the fuel system just as badly as rust. Fortunately,
the BB method works as well in plastic tanks as it does in steel
tanks. Although plastic tanks are not maintenance-free, they still
are more trouble-free than steel tanks. Thus, if you have to buy
a replacement, select a plastic tank if its available for
If you use fuel additives,
be sure they are compatible with your fuel system. Keep in mind
that manufacturers usually market these additives for automobiles.
Therefore, the containers often are scaled for a 15- to 20-gallon
fuel tank, not a 2- to 5-gallon tank. Read the label to see if
it provides specific instructions regarding how much to add. If
not, be sure to proportionally reduce the amount you add to account
for the smaller tank size.
Step 5: Maintaining
fuel- and oil-injection systems
If an oil-injection system
(most smaller engines such as trimmers and saws do not use oil
injection) requires repair, its usually because of dirt
that got into the system, not because of some problem with the
oil itself. Cleaning oil systems is simple: just disassemble them,
wash the parts and reassemble. Oil is quite stable and has a long
shelf life. Therefore, storage doesnt usually affect its
quality. The best advice I can give you is to stay with a known
brand of oil instead of a generic type.
systems are prone to some long-term storage problems. One of the
most common is gumming from varnish buildup. This will cause injector
units to malfunction. No really good way exists to drain an injector
unit completely, so the best prevention is to use chemical fuel
additives for storage instead of trying to drain the system.
If an injector still works
but you dont feel it is running quite right, you can try
additives for injection systems that you pour directly into the
gas tank. As the fuel passes through the system, it will clean
light deposits from injectors. Other than this, the only
way to repair an injector is to replace it with a new one, so
heavier deposits may require you to replace the injectors.
If you have to change an injector,
be sure to wait until all of the engine parts (especially mufflers
and manifolds) are completely cool. Moreover, be sure to clean
up any spills that happened during the repair. Remember to change
all the fuel filters as well as the injectors. This will prevent
any fuel contamination from entering your new injectors.
A few final notes
* Although it is possible
that dirt or water in your fuel system came from your fuel supplier,
dont overlook your own storage containers.
* All fuel systems benefit
from in-line fuel filters, but make sure the ones you use are
suitable for your system-fuel-injection systems use high pressure
or volume and can tear a conventional filter apart.
* Reformulated gasoline
usually contains alcohol, which has a natural tendency to draw
moisture from the air around it. If you are in a region where
reformulated gasoline is used, be aware that storing your equipment
with this type of fuel in an environment with high humidity can
cause a buildup of water in the gas just by letting it sit around.
Dont forget that this can happen with gas cans too, not
just fuel tanks.
Step 6: Consider seasonal
service for cooling systems
Up until now, this discussion
has applied to air-cooled as well as liquid-cooled engines. However,
the cooling system itself also needs attention-every year on your
liquid-cooled machines. Most equipment today is either all aluminum
or at least has aluminum heads and radiators. Thus, it is important
to use only coolants that are compatible with aluminum systems.
Fortunately, most coolants are suitable. The problem usually shows
up with fleet accounts that buy coolant in 55-gallon drums. Occasionally,
an equipment manager will purchase bulk coolant that is suitable
only for steel protection and then, forgetting this fact, use
the coolant thats on hand for all the engines.
Aluminum radiators transfer
heat efficiently until they begin to plug with mineral and dirt
buildup. Thus, you should change the coolant at least once a season.
Use distilled water when blending the 50/50 mix to prevent mineral
buildup in the cooling system. At the same time, also check all
hoses for cracks and soft spots that could cause costly downtime
the following season. In addition, inspect the belts for cracks
or other damage and check the operators log for any reported
cases of overheating. If so, now would be a good time-while the
system is drained and flushed-to replace head gaskets and thermostats.
These are the two most common causes for overheating.
Finally, always check the
coolant level and, in cold climates, check the level of freeze
protection your coolant offers. Testing laboratories can evaluate
coolants and give an indication of system wear and other problems
before they get out of hand. This type of testing is called "cool
Step 7: Dont
forget the rest of the equipment
Finally, remember that the
engine is only part of the equipment. Gearboxes and drive trains
also have special needs for seasonal storage. These components
are often sealed and forgottenuntil they fail. When they
do, they can be as costly to repair and cause as much downtime
as any engine.
When you shop, look for features
such as plastic tanks and the quality of the fuel and cooling
systems. These are often-overlooked aspects, but making the right
choices could save you a lot of maintenance expense down the road.
proper long-term storage:
a shaded, cool storage site
metal fuel tanks full, but drain plastic fuel tanks
4-stroke engines, drain the carburetor bowls
2-stroke engines and those with fuel injection, use chemical additives
(fuel stabilizers) instead of draining the carburetor
especially wary of storing reformulated gasoline, which can absorb
water directly from a humid atmosphere.
repair rusted or varnished fuel tanks:
BBs and parts cleaner in the tank to remove debris
a fuel-tank sealer to repair any pitting on the inside of the
you need to replace a tank, use a plastic replacement.
remove varnish deposits:
"choke-and-carburetor cleaner" to remove light varnish
deposits in carburetors
heavy deposits, dismantle carburetor and clean with dip-type carburetor
small air bleeds and vents, use a tip cleaner or small wire to
clear the orifice.
"fuel-injection cleaner" (fuel additive) for light varnish
deposits in the injectors
injectors with heavy varnish deposits
sure you also replace fuel filters when you service the injectors.
good cooling-system performance:
only distilled water for your coolant/water radiator mix
sure the coolant is aluminum-compatible
your coolant tested for freeze protection.