4 Common Stihl MS 291 Problems And What To Do About Them

The Stihl MS 291 is one of the most popular gas-powered Stihl chainsaws in the US because of its versatile range of operations. While not quite a professional saw, it is sufficiently powerful to handle most jobs and light enough for pruning branches.

Like every engine-driven machine, maintenance is required to keep it functioning properly, and here are some ideas to solve the mechanical problems you may experience with your Chainsaw.

Stihl MS 291 Problems

The four elements to get the gas engine running: fuel, air, spark, and compression are all essential. If one of these is missing, you will be doing some fairly heavy arm exercises in vain, so let’s look at the start-up problems first.

Hard To Start

Small gas-powered engines of now are impressively reliable compared to models of a couple of decades ago, and the Stihl ms 291 is one of the most reliable saws around.

So what could make it difficult to start?

Let’s briefly go through the correct starting procedure.

I always suggest not putting on your ear protection when starting the Chainsaw, as it is essential to hear the engine firing when the choke is fully engaged.

1. Check that the gas and chain oil tanks are full.
2. Depress the throttle and set the choke to the full position.
3. Pull the starter cord a couple of times until you hear it fire.
4. Move the throttle switch one step up and pull the starter cord again until the engine fires and then squeeze the throttle, which will release the choke, and you are ready for action.

Put your ear protection on and check that the bar is well-lubricated.

So that is the ideal starting sequence, but if the engine fails to start, the first thing to check is the fuel system.

Fuel Problems

Fuel problems fall into three categories: too little, too much, and too lean or rich.

And then, there is the age of the fuel oil mixture to consider. Old fuel is not going to do your saw any good, and it is easy to forget how old the fuel is if the Chainsaw is only used intermittently.

If the fuel is over three months old, it would be a good idea to get some fresh fuel and two-stroke oil.

Mix it at the correct ratio, and drain the chainsaw tank before you start checking the fuel system. Then, fill the chainsaw tank with fresh fuel and check the chain oil tank as well.

To check if the fuel is getting to the cylinder, set the choke to a full-on position and pull the starter a couple of times. Remove the spark plug and see if there is any fuel on the spark plug.

If the spark plug is wet, then the fuel is getting through, so it may be time to change the spark plug or at least clean it and check that the spark plug gap is correct.

Connect the spark plug on your Stihl MS291 and put it in a position where you can visually check the spark. Pull the starter chord a couple of times and check for spark.

Caution: Be very careful doing this and never touch the spark plug with your bare hands while trying this method.

If you cannot see any spark, replace the spark plug with a suitable new spark plug and check for a spark.

If the spark plug is sparking, then refit it. Next, tighten the spark plug and connect the spark plug lead again.

Repeat the starting procedure, and the Chainsaw should fire up.

Too little fuel means gas is being prevented from getting from the tank to the cylinder. Dirt in the gas will accumulate in the fuel filter, so check that first and replace the filter if needed.

It is easy to do because the fuel filter on the Stihl MS291 is inside the gas tank at the end of the flexible pipe, and the cost of a new filter is minimal.

If the fuel filter and fuel line are clean and fuel is getting through to the carburetor, it is time clean the carburetor.

Luckily, there are handy spray cans of cleaner available. Just be careful to follow the manufacturer’s instructions before spraying into the carburetor. Using a fuel system cleaning spray will save you a lot of time and effort.

Once the carburetor cleaner has done its magic, follow the starting routine again, and hopefully, your Stihl MS291 will be up and running.

Check the fuel-oil mixture. Did you follow the Stihl MS291 guide and mix the oil and gas in the correct ratio? Insufficient oil in the gas mixture is going to cause the saw to overheat.

High-Speed And Low-Speed Adjustments

Although adjustments to these screws are designed to control the engine’s performance while it is running, make sure that they are correctly set, as they will impact the engine’s rpm.

Remember it is essential that when adjusting these settings, the chain must be running, and the air filter must be clean and fitted.

It is always a good idea to warm the engine up before adjusting these settings.

Dirty Air Filter

So far, we have tested the fuel supply and ignition systems, and if your Stihl MS 291 problems still persist, we will have to check the air supply.

Fortunately, cleaning the air filter on the Stihl MS291 is simple.

You will have to remove the cover to get to the air filter, and the air filter has two holding screws attaching it to the body of the saw.

Remove the air filter and clean it thoroughly. I normally use an old brush to wipe away the dirt on the filter. Once the air filter is clean, refit it and replace the cover.

Then, check to see if the Stihl ms 291 starting problems are over.

Engine Power Problems

A couple of issues may make your Stihl MS291 lose power, let’s take a look.

Insufficient Compression.

A damaged piston or cylinder on your Stihl MS291 is going to cause the saw to lack power and create starting problems.

A similar situation will also occur if the spark plug is not securely tightened in the cylinder head.

If the saw does have a compression problem the resistance on the starter cord will be minimal.

If there seems to be reduced resistance when trying to start the saw, check the tightness of the spark plug first.

If the spark plug is fitted correctly and there is low compression the cylinder will have to be removed and the condition of the piston and the cylinder will have to be checked in order to fix the problem.

Scars of the cylinder or a damaged piston will usually call for replacement parts to be ordered and replaced to fix the problem.

Clogged Spark Arrestor

The typical symptoms of the Spark Arrestor being blocked are the chainsaw engine will start, but as soon as you pull the trigger to up the rpm, the motor will die.

Be sure the low and high-speed settings are correct before deciding on the Spark Arrestor being blocked.

On the Stihl ms 291, the spark arrestor is located in the exhaust. The spark arrestor is to prevent sparks from leaving the exhaust and possibly starting a fire.

Please do not be tempted to remove the Spark Arrestor and not replace it.

There are several ways to clean the spark arrestor, and the handy spray can of carburetor cleaner can serve another function here.

After removing the spark arrestor, give it a good spray with the carburetor cleaner and let it soak in to remove the buildup on the wire screen.

Then, using a wire brush, remove the residual bits stuck to the screen and replace the arrestor in the exhaust.

Chainsaw Overheats

If your chain tension is incorrect, you will have a problem with the chainsaw.

While a chain that is too loose is dangerous, too much tension on the chain will put too much strain on the engine and it will behave in a similar fashion to the dirty spark arrestor problem.

Along with the correct tension, regular checks on the lubrication of the bar will ensure trouble free operation.

Keep The Chainsaw Clean

Saws operate in a location where dust and debris are a problem. The Stihl ms 291 is designed to handle such conditions but it does require regular cleaning.

Check that the fins and areas that draw in cooling air are clean and open. It is just as important to ensure that the path of the hot exhaust gasses are also free of obsticals.

A blunt chain or an incorrectly tensioned chain will cause the chainsaw to overheat.

Remember that the Stihl ms 291 is not designed for long periods of operation so on a hot day it may require some rest after an hour or two of heavy cutting.

Things To Like About The Stihl MS291 Chainsaw

Stihl and Husqvarna are two of the most well known and trusted brands of chainsaws. The competition is fierce and consequently manufacturers are consistently looking for ways to improve the quality of their products.

The Stihl ms 291 is light enough for easy handling, and yet, it also has enough power to get through a serious amount of cutting without too much trouble. It is the ideal chainsaw for cutting firewood and doing pruning.

It has an impressive economy rate and its emission levels are low.

Stihl MS 291 Specs

Displacement cc55.5

Power output kW/bhp2.8/3.8

Power-to-weight Ratio kg/kW2

Sound pressure level dB(A) 2)103

Sound power level dB(A) 2)116

STIHL Oilomatic saw chain pitch/type .325 ”

Tank volume mL500.0

Availability Of The MS291 Chainsaw

Stihl has a policy of selling their machines only through authorized agents. The brand has an international presence and their chainsaws are available throughout the USA.

Ace Hardware and other rural type hardware stores often carry Stihl chainsaws.

Final Thoughts

Quality brands like Husqvarna, Stihl, or Echo are continuously improving the technology of their chainsaws to make them easier to use, more efficient, and environmentally friendlier.

Keeping your chainsaw clean makes for a more efficient machine that will start and run much better. Chainsaw work is dusty, and the dust particles will accumulate in the engine to create problems if they are not removed.

The added presence of bar oil means that wood chips will collect, particularly around the sprocket area, and cause problems if not removed.

Frequently Asked Questions (FAQ):