This article covers topics fundamental to care and operation of a chainsaw.
Chainsaws
come in many different makes, models and sizes. What follows is
general overview that covers topics general to all gas powered units.
It is highly advisable to carefully read the owner’s manual for
your saw before attempting to apply what is discussed here. If you
chucked the manual somewhere in the deep dark recesses of your shop
and can’t find it, check the companies website. Many of these
websites contain a lot of very useful information, and some are better
than others. The author assumes no responsibility for any injury or
damage caused by readers following suggestions contained herein.
Chain,
chain, chain…
The
whole point of a chainsaw is to cut, so we’ll start with that end
of the machine. There are basically two parts to the chain, the
cutter and the links. The links are between left and right hand
cutters. The chain may also have some features that prevent kickback.
Kickback occurs when the saw jumps back toward the operator while
cutting. You really do want to avoid this because it can be the
source of serious personal injury. It can leave you looking like the
victim in one of those chainsaw horror movies. So, you need to make
sure that the parts of the chain designed to prevent kickback are in
good shape. This will be discussed more later on.
Chain
pitch is half of the distance measured between the centers of any
three consecutive rivets in the chain. Pitches come in sizes ranging
from 0.25 to 0.75 inches for standard size chains. You need to know
this when shopping for a new chain. The chain may also include bumper
tie straps, bumper links and ramped depth gauges (on the cutters).
These prevent kickback, and if your old chain has them, make sure
your new one does too - this is very important. You also need to know
the size number of the of the chain, this is usually stamped on the
side of the chain’s drive links (the drive links sort of look like
shark‘s teeth and are on the bottom side of the chain). The pitch
and size number correspond. You should also know the gauge of the
chain. This is the thickness of the drive link and determines how
well the chain fits into the guide bar (that big flat bar the chain
rides on).
Unless
they have been damaged, or just plain worn out, chainsaw cutters can
be sharpened. This takes some skills and knowledge that most
do-it-yourself types don’t have and so it is well worth the expense
of having a professional sharpen the cutters. An improperly sharpened
chain can cause severe kickback, vibration, and serious injury. Or,
it may simply not cut, causing the operator to put undue pressure on
the saw and increasing the likelihood that the saw will slip and
injure the operator. Proper sharpening and care of the chain is
crucial to operator safety, don’t scrimp.
As
a new chain is used it will stretch. As it does it becomes slack on
the guide bar and needs to be adjusted. If left that way, the chain
will eventually jump off of the guide bar. At the same time, the
slack chain will be causing damage to the guide bar and the drive
sprocket that makes it rotate, so it is important for your safety,
and life of your saw, to adjust the chain periodically. Check the
manual for your saw on how to do this, different makes and models may
have slightly different mechanisms.
Many
manufacturers put an adjusting screw on the saw right on the end
where the bar sticks out of the unit. To adjust the tension on the
chain all you do is slightly loosen the bolts that hold the bar on
and then turn the screw in until the slack is gone from the chain.
With the chainsaw sitting on a workbench or table, adjust the screw
until the bottom of the chain links on the underside of the guide bar
just touch the bar. You should not be able to see the drive teeth of
the chain; they should be inside the bar, with the bottom of the
chain link just touching the bar. That’s enough tension. Putting
too much tension on the chain can damage the guide bar, so you want
just enough, but not too much. Then tighten the bolts that hold the
guide bar on.
If
you are putting a new chain on, check that the shoulders of the guide
rail are square and not rounded off or worn unevenly. If they are
worn, the new chain will wear unevenly, thus shortening its lifespan
considerably. Also check to make sure the guide bar is straight and
not bent to one side.
Lubrication
& fuel
Both
the chain and guide bar require lubrication. The guide bar is
lubricated by oil that the chain carriers with it as it goes around
the bar. Usually, a chainsaw will have either a pressure lubrication
system or a gravity lubrication system for the chain. The pressure
system usually has an adjusting knob to regulate the flow of oil. If
the flow keeps on decreasing and you have to keep adjusting for it,
there is likely some dirt in the oil tank and/ or oil filter. The
cure is to remove and clean out the tank and change the oil filter.
As
for lubricating the engine, be sure to follow the manufacture’s
recommended fuel mixing ratio. To mix gas and oil put some of the gas
in your container, add the full amount of oil you will need and
swish. Then add the rest of the gas needed and swish a little more.
This way the gas and oil are more thoroughly mixed, which provides
better, more consistent, lubrication to the chainsaw engine. Adding
too much oil will cause the chainsaw to be hard to start, excessive
smoking, a fouled spark plug, and can plug up the exhaust port. Not
enough oil in the mix will cause the chainsaw to overheat and will
damage all the moving parts in the engine through lack of
lubrication. Mix just enough fuel for the cutting season. If you must
store the mixture during the off-season, add some fuel stabilizer
following the directions that come with it. Also, in preparation for
storage, run the chainsaw until it is out of fuel, and then give the
pull rope 3 or 4 pulls to make sure all fuel is used up and out of
the fuel system. Do not store a chainsaw with fuel in it, it will
likely clog up the tiny passages in the carburetor preventing the saw
from starting when you need it.
Take
a brake.
If
your chainsaw is equipped with a chain brake, for safety sake, make
sure it is in working order. Over time sawdust and oil can accumulate
inside the engine cover, around the area of the chain brake. This can
cause the brake to slip, or not engage properly. If your manual gives
directions on how to service this you can give it a try yourself, if
not take the saw to a trained mechanic. He or she can perform this
service as part of a tune up and thorough cleaning, which your saw
should have periodically.
Check
these out.
Here
are some things you should check regularly when you go to use your
chainsaw. Refer to your owner’s manual, or the company website for
directions and specifics for your make and model of saw.
Check
that the tension on the chain is properly adjusted and that the
cutters are sharp and not damaged.
Make
sure the chain brake works if your saw has one.
Check
the on/off switch and throttle trigger. They should move freely.
Run
the saw for about a minute without cutting in order to check the
flow of oil to the chain.
Clean
the air filter regularly.
If
it is possible with your saw, take the bar off and turn it over
occasionally to equalize wear on both sides.
Clean
the spark plug and check the gap. Set the gap at .025 to 0.30” or
whatever the manual calls for.
Clean
oil and sawdust off the exterior and from around the engine’s
cooling fins.
Grease
the end sprocket on the bar.
Lubricate
the clutch bearings if required.
Clean
the spark arrester (located inside the muffler).
Check
the fuel filter (located inside the fuel tank) for dirt. It can be
fished out with a wire.
Top
up the oil tank.
Tips:
Before
putting a new chain on, soak it in bar oil overnight.
Run
a new chain for a few minutes, without cutting, and then readjust
the tension. Adjust the tension frequently for new chains; it takes
time for them to stretch in.
Do
not allow the chain to hit dirt while cutting, it quickly dulls the
cutters.
Always
wear proper safety and protective gear when operating a chainsaw.