Starting a Stihl MS250 correctly is the foundation for safe and efficient woodcutting. This reliable professional-grade chainsaw requires a specific sequence of actions to ensure the engine fires properly and runs smoothly from the first pull. Following the correct procedure minimizes wear on the starter rope and prevents common issues like flooding, which can occur if the process is rushed or performed incorrectly.
Pre-Start Safety Checks
Before you even touch the starter cord, a series of safety checks is non-negotiable. Operating a chainsaw without verifying these items puts you at serious risk. Ensure the chain brake is engaged and the chain is sharp and properly tensioned for effective cutting. Additionally, confirm that the fuel tank is filled with the correct gasoline mixture and that the bar oil reservoir is adequately supplied to prevent damage to the saw.
Personal Protective Equipment
Your safety gear is the last line of defense against injury. Prior to starting the engine, you must be wearing appropriate personal protective equipment (PPE). This includes sturdy work boots, cut-resistant trousers, eye protection, and hearing protection. Never attempt to start the saw while it is in contact with your body or clothing, as the recoil can cause severe injury.
Step-by-Step Starting Procedure
The Stihl MS250 features a decompression valve and a choke control to simplify the starting process, especially when the engine is cold. Mastering this sequence ensures a reliable start every time, whether you are felling trees or pruning branches. Follow these steps methodically to avoid frustrating false starts.
Priming the Engine
Locate the fuel primer bulb, typically situated near the air filter cover. Press the bulb several times until you feel it becoming firm and resistance increases. This action pushes fuel into the carburetor, eliminating air pockets and preparing the system for ignition. Skipping this step often results in a difficult start or the engine sputtering and dying.
Setting the Choke
Identify the choke lever, usually found on the side of the engine. Move the lever to the "Closed" or "Choke" position. This restricts the airflow entering the engine, creating a richer fuel mixture necessary for combustion when the engine is cold. If the saw has been running recently and is warm, you can leave the choke in the open position.
Executing the Pull
With the choke set and the primer bulb filled, you are ready to initiate the starting process. Position yourself to the side of the saw to avoid the recoil path and ensure the chain is clear of any obstructions. A firm and decisive pull is required to engage the starter and ignite the fuel mixture.
Quick Release Technique
When pulling the starter rope, avoid yanking it slowly like pulling a lawnmower. Grasp the handle firmly and pull briskly in one smooth motion. If the engine does not start, release the rope completely to allow the recoil spring to reset. Repeat the process, adjusting the choke as necessary once the engine begins to fire. Troubleshooting Common Issues Even with the correct procedure, you might encounter issues that prevent the MS250 from starting. Understanding the mechanics behind these problems allows you to correct them quickly without unnecessary frustration. A flooded engine is one of the most common hurdles faced by operators during the starting process.
Troubleshooting Common Issues
Addressing a Flooded Engine
If you smell unburned fuel or notice the spark plug is wet, the engine is flooded. This occurs when too much fuel enters the cylinder, preventing the spark plug from igniting the mixture. To resolve this, set the choke to the "Open" position, pull the starter rope vigorously five to ten times to clear the excess fuel, and then attempt to start the saw again.
