The Stihl MS 250 is a popular model of chainsaw ideal for homeowner use. However, like any power tool, it can experience issues from time to time.
This article will cover some of the most common Stihl MS 250 chainsaw problems and provide troubleshooting tips to get your saw running again.
Running Lean and Bogging Down
One of the most frustrating problems you may encounter with your MS 250 is it running lean, sputtering, and bogging down during cuts.
There are a few potential culprits that could cause this issue:
Clogged Air Filter
Over time, sawdust and debris can build up on the air filter, restricting proper airflow into the carburetor. This lack of air causes the fuel mixture to run lean.
To fix, remove and clean or replace the air filter.
Similarly, a carburetor clogged with gum, varnish, and dirt can also restrict air intake.
Cleaning the carburetor with carb cleaner and compressed air will restore proper airflow and fuel mixture.
Faulty Fuel Pump
The fuel pump pulls fuel from the tank and delivers it to the carburetor. A malfunctioning fuel pump will cause lean running. Test the pump and replace it if faulty.
If you pull and pull but the chainsaw engine won’t start, there are several things to check:
Faulty ignition components like bad wiring, defective electronic ignition module, fouled spark plug, or bad ignition coil can prevent the engine from starting. Test and replace any faulty parts.
Clogged Air Filter
As discussed above, a dirty air filter also commonly contributes to start-up issues.
Varnish buildup in the carburetor can clog passages and restrict fuel flow, preventing starting. Clean the carburetor thoroughly.
Check that fuel is reaching the carburetor. The fuel filter may be clogged or the fuel lines cracked. Replace defective parts.
Without good spark to ignite the fuel mix in the cylinder, the engine won’t start. Spark issues in the MS 250 are usually electrical:
Inspect the spark plug. If fouled or damaged, replace it. Ensure the gap is set correctly.
The ignition coil converts low voltage from the magneto to high voltage for the spark plug. Test the coil and replace it if faulty.
If the chainsaw is very hard to pull over and has low power, it likely has low engine compression. This is usually caused by:
A scored or stuck piston will reduce compression. The piston must be repaired or replaced.
Similarly, a cylinder scored from lack of lubrication or with stuck rings will cause compression issues. This requires cylinder repair or replacement.
For significant engine issues like damaged pistons or cylinders, it’s best to take the saw to a professional repair shop.
With regular filter changes and carburetor cleaning, you can prevent many common problems with the Stihl MS 250 saw. But when trouble does strike, this guide will help you troubleshoot and fix the most common issues that can arise.
With basic maintenance and repairs, your trusty Stihl chainsaw will be back cutting in no time.