Should I Buy A Used Chainsaw? Here's why I wouldn't...

A chainsaw is a great tool to have in the woodshed. They can be quite temperamental, so choosing to buy a used one may not be the best choice.

Buying a used chainsaw is not advisable as they are hard to tune, especially if they have been dropped or cracked.

There are many different yard tools available; some will last forever if well maintained, while others won’t. Chainsaws are like the diva in the woodshed. With lots of attention, they run like a dream, but if not, they will break your heart.

What Are You Going To Use the Chainsaw For?

Picking the correct tool for the job is half the battle. There are many different types of chainsaws available: gas and oil (2-stroke), electric battery, and electric corded. Selecting the correct chainsaw for you will depend on what job or chore you require it for.

Light cutting of timber with a light chainsaw will be sufficient, but if you intend to fell trees, then a larger two-stroke saw will be required.

Choosing the Correct Saw

Unlike many yard tools, a chainsaw used incorrectly can have fatal consequences. It is not a tool to be complacent about. Although there are safety features, you must be aware of your own physical capabilities. If you can’t hold a saw for any length of time, then you must choose a lighter one.

Choosing a new vs. a used saw has the benefits of a vendor showing you the correct procedure for use and all the safety features. That’s not to say a seller of a used saw won’t be as thorough; however, due to it being a used saw, the safety features may not work as well as they should or may be compromised altogether.

Cost of a Chainsaw

If you are considering buying a used chainsaw, then the cost is going to be a big part of the discussion. A new chainsaw cost will range from $100 – $600 depending on the size, brand, and power source. Gas is more expensive than electric or corded, but gas-powered have more capabilities out in the field.

The average medium/ heavy duty is going to set you back approximately $200. So why am I talking about new chainsaw prices when you’re asking if I should buy a used one?

Problems with Used Chainsaws

The thing about buying a used chainsaw is, what are you really buying? Why is the person selling the saw? Chainsaws can be temperamental. Gas-powered saws are two-stroke engines. This means they don’t have an internal oil reserve, but the user must pre-mix the gas and oil.

The gas-oil mix is critical to the health of the saw.

The two-stroke refers to the number of strokes of the piston head – the piston moves once (first stroke) and moves the crankshaft halfway (air and fuel move down the cylinder), and then the second stroke completes the cycle (air and gas is compressed ready for combustion).

It’s important to understand engines don’t run on gas alone, they also require air (oxygen), and they prefer a particular Air to Fuel Ratio (AFR). If the AFR is out, you’ll know about it pretty quickly, no power, erratic performance, and the list goes on.

The ratio is 14.7 parts air to 1 part gas, and a carburetor controls this ratio. A chainsaw should idle smoothly – too much air; your saw will surge (running lean); too much gas (running rich or fat), it will splutter.

The point is it doesn’t take a lot to put the AFR out on a saw, but it could take a ton of work to put it right. Often a simple adjustment of the H and L screws will solve the issue, but sometimes it may take a rebuild to put it right.

I’ve covered carburetor adjusting previously, and you can check it out here.

Surging Engine

A used chainsaw, being used will have some issues. AFR issues are common, and as said in many cases, carburetor tuning may fix them, but often, there’s something else going on. Something that can’t be tuned out, and in some cases, this won’t be apparent until the saw gets up to working temperature.

The problem with a used chainsaw is you don’t know the history. The nature of their work means they are outdoors, and the biggest concern is – Has the saw has been dropped or something heavy (a tree!) fallen on it. A chainsaw is a sealed unit; the outer casing for many saws is part of the engine, and it’s critical it’s airtight.

A heavily dropped saw may develop cracks in the body. So why does this make a difference? Back to our AFR. If the body (plastic) is cracked, then air will enter the engine unmetered. This will disrupt the AFR, and you will never get your chainsaw to run sweet.

Many chainsaws are sold for this reason. Watch out, especially for saws with new carburetors; this indicates the seller tried to repair but discovered the problem wasn’t the carburetor. A seller, unfortunately, may not tell you that the saw has a problem.

Need info on a 2-stroke carburetor – check out – How does a 2-stroke carburetor work?

Dirty Carburetor

With chainsaws, it’s all about the AFR. Dirt in the carburetor or gas filter is a common root cause of a ton of chainsaw poor performance or no-start issues. One of the most common problems is storing a chainsaw with gas in the tank.

Chainsaws can’t be left with fuel in them for any length of time (more than one month), as it goes stale and cause gumming in the carburetor.

A gummed carburetor prevents proper fuel delivery, and this means no matter how hard you try, you won’t get the saw to run properly by tuning the carburetor. The carb, at best, will need to be cleaned or, at worst, replaced.

But remember, a used saw price must make sense; not much point in saving money on the purchase price only to make up the price of a new one by adding new parts or a ton of time-wrenching.

Gumming can be avoided, by the way, by using a gas stabilizer in the fuel system when storing. I covered it here in the video – “Mixing and adding gas stabilizer.”

The video shows it being added to a lawnmower, but it works for all gas-powered engines. However, you should know this is not a substitute for two-stroke oil and should be added last after you’ve mixed your two-stroke gas mix.

Low Compression

Gas saws, as you know, are two-stroke, meaning oil must be mixed with the gas. It’s this oil that prevents engine damage. It is critical, therefore, that the oil is at the correct ratio. Incorrect oil mix is common among light occasional saw users.

Getting the oil mix wrong can cause irreversible piston and cylinder damage. In the worst-case scenario, the engine seizes, meaning the internals fuse together.

You’ll know a seized saw as the pull starter won’t turn the engine.

But the damage can occur before the engine actually seizes. Scoring of the cylinder, rings, and piston wear results in low cylinder compression.

The symptoms vary depending on how bad it is; typically, it results in no or hard starting, idling issues, lack of power, and won’t idle, hold the throttle, or hot start.

You’ll find the cost of repairing such a saw likely uneconomical.

Safety Features

The most important chainsaw safety feature is the Chain break. When a saw tip bites into the wood, it can sometimes kick the saw tip upwards violently.

The chain brake is a handguard designed to make contact with the operator’s hand automatically in the event of a kickback. When the operator’s hand makes contact with the spring-loaded guard, it activates the chain brake, which, as its name suggests, stops the movement of the chain immediately.

Kickback is rare these days as chains and bars are designed to minimize them. That said, incorrect saw use will produce kickback, and you most definitely want your chain brake to work.

Chain & Bar Issues

The two most likely components to be damaged on a chainsaw are the chain and the chain bar. These are the business end of cutting and are obviously important. A lack of oil is a common root cause of a badly damaged bar and chain.

That said, bar and chain are wearing items that can be easily replaced and are relatively inexpensive.

Chainsaw Oil Pump

The chain saw has an oil pump, not for the engine; it’s two-stroke. No, the oil pump is for the chain and bar. Oil is delivered to the bar and chain to help reduce friction, which in turn reduces heat and keeps bar and chain wear to a minimum. In addition, it helps maintain a sharp chain, and a well-lubed chain reduces the chances of kickback.

Pumps do wear out and become clogged. Some operators use waste car engine oil in the bar oil reservoir, shortening the pump, chain, and bar life.

The problem is when the pump lets go and stops delivering oil to the bar, some serious knock-on effects are common.

They are as follows:

Increased chance of kickback
Increased bar wear
Increased chain wear
Overworked engine
Excessive heat transfer to saws plastic body
Excessive vibration to saws body

Other Common Used Chainsaw Issues

Still think buying a used saw is a good idea? Here’s a collection of other issues you may need to deal with. Not all serious, but all are defo a pain in the ass to repair.

Sticking throttle
Perished fuel lines
Cracked carburetor intake mount
Carburetor gasket vacuum leaks
Worn out carburetor
Pull cord and or pawl wear/broken
Broken engine mounts

All of the above are of course repairable and you’ll find links to a ton of chainsaw repairs here on the Chainsaw troubleshooting page.

New Saw is the Better Choice

A used chainsaw is not worth the cheaper price tag unless you know and trust the seller or are permitted to run and cut timber with the saw until hot; I’d pass on the deal. The time you will spend ‘fiddling’ with the carb to get it to run properly is just not worth it.

Unless you have a thing for bringing old yard tools back to life, I would steer clear of a used chainsaw. It will burn your time and may also be a serious safety hazard.

A used saw from a saw dealer is fine. Presumably, it will be serviced, safety checked, and come with a warranty.

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Chainsaw Troubleshooting Index