7 Most Common STIHL MS 261 C-M Problems and Effective Fixes

STIHL chainsaws are popular among home users, tree care workers, and professional arborists. If you’re looking for a high-quality, all-around chainsaw, the STIHL MS 261 C-M is worth considering.

This chainsaw features the advanced STIHL M-Tronic technology that boosts its performance in various applications. It’s lightweight, fuel-efficient, and delivers low emissions. Despite all these impressive features, this chainsaw has several issues. The most common STIHL MS 261 C-M problems are failure to start, carburetor issues, acceleration problems, insufficient airflow, idling failure, oiler issues, and smoky odor.  

Do you own a problematic MS 261 C-M? Keep reading and learn how to fix your STIHL chainsaw.

STIHL MS261 Won’t Start

Starting problem is the most reported issue with the MS 261 C-M chainsaw. It’s also a common problem with chainsaws from other brands. Luckily, various troubleshooting techniques exist to fix and get your chainsaw back to work.

This chainsaw might fail to start due to the following issues:

• Insufficient fuel
• Clogged air filter
• Faulty spark plug
• Bad fuel solenoid

Effective Fixes:

The fuel tank is the first to check if your chainsaw fails to start. If it’s empty or the level is too low, fill it with fresh fuel as required.

Does the fuel appear cloudy or dark? If so, drain it and flush a fuel injector cleaner through the fuel lines to clean off any residues. Fill the tank with fresh fuel and run the engine.

While still in the fuel system, test the fuel solenoid with your multimeter to see if it’s functional. If it’s defective, replace it.

A clogged air filter can block air from getting into the combustion chamber. So, clean the clogged filter or replace it if it looks old or worn.

Then examine the spark plug and replace it if it’s faulty.

Carburetor Issues

The carburetor needs regular care and maintenance to ensure your chainsaw performs smoothly. If you neglect it for an extended period, it might lead to engine starting, loss of power, overheating, and stalling issues.

Several issues might cause the MS 261 C-M carburetor to malfunction. They include:

• Clogged carburetor
• Misadjusted carburetor
• Bad carburetor

Effective Fixes:

The carburetor will clog up over time and cause starting, loss of power, and stalling. Dirt, debris, and residue from the fuel can block the carburetor over time.

Remove the carburetor and use carb cleaning brushes to remove the stuck dirt and debris. Then soak the carburetor in a carb-cleaning solution to remove the stubborn gunk.

If the issue results from a misadjusted carburetor, use the operator’s manual to adjust it properly.

Lastly, take the carburetor to a professional to diagnose and repair a defective carburetor. Your professional might recommend replacing the carburetor if it’s too old or damaged beyond repair.

Acceleration Problems

Poor acceleration is one of the most common STIHL MS 261 C-M problems. If your MS 261 C-M has weak acceleration, the causative factors could be:

• Insufficient lubricant
• Improper chain tension
• Problematic engine

Effective Fixes:

The chainsaw might bog down during acceleration due to insufficient lubricant on the chain. Inspect the chain to see if it’s well-lubricated. If not, check the oil level and fill the reservoir with the recommended oil.

Does the chain appear too tight or loose? Improper chain tension can cause acceleration issues. An overtightened or loose chain can cause poor performance and safety issues. Adjust the tension level to ensure the chain is tight enough with a slight looseness.

If the acceleration problem persists, the engine might have issues and needs repairing. Take your chainsaw to a specialist to fix the engine.

Insufficient Airflow

The engine of your STIHL MS 261 C-M requires enough air to burn fuel properly and perform smoothly. Unfortunately, this chainsaw might experience airflow issues that can cause the engine to bog down, consume a lot of fuel, and overheat.

The engine might also experience difficulties while starting. If it starts, it might lose power, release a lot of smoke, and stall.

If your engine doesn’t receive enough air, the culprit could be a failing air inlet. Your chainsaw might have a clogged air filter or damaged air intake housing.

Effective Fixes:

Dust and debris can block the air filter and prevent it from supplying cool air into the engine. So, remove the filter and examine it. If it appears dirty or clogged, use warm, soapy water to clean it. If it’s old, worn, or damaged, replace it.

Next, inspect the air intake housing and clean it if necessary. If you have a broken or damaged air intake housing, replace it.

Idling Failure

The STIHL MS 261 C-M needs to idle properly after hours of operation. Idling allows the engine to cool down to ambient operating temperature. You’ll need to adjust the idle speed screw to ensure the engine idles appropriately.

Unfortunately, the chainsaw is prone to idling failure and can overheat, causing damage to the engine components. Some users claim that the engine idles for a while and cuts out.

Idling failure is among the STIHL MS 261 C-M problems resulting from improper maintenance. The possible culprits could be:

• Carburetor icing
• Damaged idle adjustment screws

Effective Fixes:

The carburetor is the first component to check if your chainsaw has an improper idling issue. The carburetor might have iced up if you stored the chainsaw for a long time, especially in cold weather. An icy carburetor causes fuel inside to cool and affects its flow.

To remedy the icy carburetor problem, let the engine heat up to about 50° F (10° C).

If the idling issue persists, inspect the idle adjustment screws. If they appear loose or damaged, replace them.

Oiler Problems

The chain oiler lubricates your STIHL MS 261 C-M chain and guide bar to allow smooth operations. Over time, the oiler can develop issues and fail to lubricate the bar and chain. When this happens, the bar and chain can overheat, damage the bar and cause acceleration issues.

The following issues can cause chain oiler problems.

• Clogged oil inlet hole
• Clogged oil filter
• Defective oil pump
• Damaged oiler line

Effective Fixes:

Sawdust, dirt, and other debris can clog up the chain oiler and prevent oil flow to the chain and bar. So, check the air inlet hole, oil pump, and oiler line for clogs. Clean them with hot water and remove stubborn stuck debris or gunk with a wire brush. Then replace the clogged oil filter.

If your chainsaw has a worn or defective oil pump or oiler line, replace them.

Smoky Odor While Cutting

The smoky or burnt smell while cutting is a common problem among chainsaws. However, you should not ignore this issue as it might cause serious problems over time.

The causative factor could be a dull chain if you notice a smoky odor from the wood while cutting. Moreover, insufficient lubricant on the chain and guide bar can cause this problem.

Effective Fixes:

The combustion process in your MS 261 C-M will produce a smoky odor. However, examine the chain to see if the smoky odor comes from the wood while cutting. Sharpen the chain appropriately if it’s dull.

Then, check the guide bar and chain to see if insufficient lubricant is the cause. If they’re not properly lubricated, check for low oil levels in the reservoir. Refill the reservoir with the recommended oil if necessary.

Are STIHL MS 261 C-M Problems a Deal Breaker?

While the MS 261 C-M has several issues, it’s one of the best chainsaws in the market. STIHL ensures you get a high-quality and durable chainsaw with innovative technology. Its engine is powerful enough to handle various cutting tasks, from pruning branches to felling trees.

Most STIHL MS 261 problems are common to other chainsaws. If you can’t resolve a problem with your chainsaw, take it to a specialist to fix it. Lastly, maintain your MS 261 C-M to avoid these issues or reduce their severity.