Starting a Stihl MS250 chainsaw correctly is the foundation of safe and efficient woodcutting. This reliable tool requires a specific sequence of actions to ensure the engine fires up properly and runs smoothly from the first pull. Understanding the preparation steps, the choke setting, and the proper handling technique transforms a potentially frustrating task into a straightforward process. This guide walks you through every step to get your saw ready for work.
Preparation and Safety Checks
Before you even touch the starter cord, a series of safety and preparation checks is non-negotiable. A chainsaw is a powerful tool, and respecting its operation starts long before the engine ignites. Skipping these steps increases the risk of accidents and equipment damage. Ensure you are in a stable position with secure footing before proceeding.
Verify the chain brake is engaged by pushing it forward; it should lock firmly.
Check the fuel level and ensure the tank is sealed securely.
Inspect the bar and chain for proper tension and lubrication.
Confirm the area around the saw is clear of debris and bystanders.
Setting the Choke
The choke regulates the air-fuel mixture entering the engine, which is critical for a cold start. For a Stihl MS250, you must locate the choke lever, typically situated near the air filter cover. If the engine is cold, you will need to set the choke to the "Closed" position. This enriches the mixture, making it easier for the spark plug to ignite the fuel when you pull the cord.
Locating the Controls
Familiarize yourself with the three main controls around the starter: the throttle lock, the idle screw, and the choke. The throttle lock prevents accidental movement, so you must press it down to move the throttle trigger. The idle screw adjusts the speed when the saw is running, but initial startup is the critical phase. The choke is your primary focus for getting the engine to fire.
The Pull Sequence
With the choke closed and the chain brake engaged, grip the handle firmly with your right hand, ensuring your trigger finger is resting naturally along the top of the handle. Use your left hand to support the base of the saw on the ground. Execute a smooth, decisive pull of the starter cord. Do not jab or yank the cord violently; a fluid motion generates the necessary compression to start the engine.
Priming the Engine
If the saw has been sitting for a while or struggles to start, you may need to prime the engine. Locate the small rubber bulb on the carburetor and press it several times until you feel resistance. This action pushes fresh fuel into the carburetor bowl. After priming, return the choke to the "Open" position slightly or fully, depending on whether the engine fires up, to allow the saw to run at the correct temperature.
Adjusting and Running
Once the Stihl MS250 fires up, let it run for a few seconds at idle. You will then need to adjust the choke to transition the engine to normal running speed. Gradually move the choke lever to the open position; you should hear the engine speed increase and stabilize. If the engine dies, you may have opened the choke too quickly; gently adjust it back until the saw runs smoothly.
After the saw is running, release the throttle lock and pull the trigger slightly to set the idle speed. The chain should remain stationary while the engine is idling. If the chain moves, adjust the idle screw clockwise or counterclockwise until the chain stays still. Only when the saw is running at a stable idle should you proceed to load the guide bar and begin cutting.
