A well maintained saw will run for years, the most important thing to remember about chainsaw carving is that you cannot do anything without a sharp saw, you will not be able to make even one straight cut into your wood without a sharp saw, I will outline the steps to creating a sharp saw with a round file. The chainsaw chain has a unique method of cutting wood the chain removes wood with the top of the chain.
A dull chain will have the top and the hook worn away or bent over
The amount of wood removed each time the tooth passes through the cut is determined by the height of the "raker"
If the raker is too high then the saw will not cut into the wood very fast, but sometimes this is a desirable affect for shaping and contouring.
The saw chain must have the correct "hook" as well this helps for a smooth cut
the hook must be low enough from the top of the tooth too curl the wood away from the cut. all this is accomplished with a stoke of the file, either a two handed stroke or a one handed stroke, stroke angle determines the hook size as
Place the saw on a solid surface or in a bench vise to begin, make sure you are using the correct size file for your chain, you can ask this when you purchase your saw, a file handle is also required so that the right pressure to the file can be applied, the file must be pressed hard enough to cut the tooth.
Start with the correct position and file drawn back
Push the file across the tooth while pushing down (black arrow) and back, (yellow arrow) also maintain the original angle of your chain
Start again from the beginning of the stroke and repeat until the top of the chain has a straight sharp edge, continue through all the teeth until the entire chain is sharp, if your tooth angles are not the same on both sides of your chain then the saw will not cut in a straight line, most chain has a small line at the back of the tooth to help you maintain the proper angle
There are guide tools you can purchase to help you file correctly but they are slow and cumbersome.
Chainsaws have two stroke engines, this means that there is no motor oil in the engine, instead the oil must be mixed into the gas, if the ratio of motor oil to gas is too low the saw engine will seize up and you will be looking at a few hundred dollars in repairs, always follow the manufacturers recommended mixing ratio for your saw,

Cleaning the air filter is important as well
A clean filter will allow the saw to get enough air to run at maximum RPM making a better cut, clean with warm soap and water and dry before replacing.
The proper chain tension is important to prevent chatter when cutting or contouring, too loose and your cut will be rough.
you should be able to pull the bottom of the chain about a quarter inch from the bar, if you can do this then the chain is tight enough.
Screws are located on the top of the cover to access the air filter
Nuts to loosen the chain bar are located on the side of the saw
The carburetor is located under the air filter
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How to sharpen and maintain your carving saw
Pic of sharp tooth
Arrows indicate presure
Angle guide
File guide tool
Chain grinder
Pic of raker
Dirty filter
Pic of hook
Ten degree tilt
25 degree angle
Start of stroke
Proper chain tension