Can you start a Stihl MS250 chainsaw without a starter rope? No, you need the starter rope to initiate the engine. This guide will walk you through the simple steps to get your Stihl MS250 chainsaw up and running, covering everything from fuel to safety.
The Stihl MS250 is a popular choice for homeowners and semi-professional users due to its power, durability, and ease of use. However, like any gasoline-powered tool, it requires proper handling and a specific starting procedure. This article provides a comprehensive, step-by-step guide to starting your Stihl MS250, along with essential maintenance, safety, and troubleshooting tips.
Image Source: i.ytimg.com
Preparing Your Stihl MS250 for Starting
Before you even think about pulling the starter cord, proper preparation is crucial. This ensures not only a successful start but also the longevity of your chainsaw.
Fueling Your Chainsaw: The Right Mix
A correctly mixed fuel-to-oil ratio is paramount for a Stihl MS250. Using the wrong mixture can damage the engine.
The Stihl MS250 Fuel Mixture
Stihl recommends using a high-quality, two-stroke engine oil specifically designed for air-cooled engines. The standard Stihl MS250 fuel mixture is 50:1. This means for every 50 parts of gasoline, you add 1 part of Stihl two-stroke oil.
- Gasoline: Use fresh, unleaded gasoline with an octane rating of 89 or higher. Avoid using ethanol blends if possible, as they can degrade fuel lines and seals over time.
- Two-Stroke Oil: Always use genuine Stihl two-stroke oil or an equivalent high-quality oil.
- Mixing: For a 50:1 ratio, you can mix:
- 1 gallon (3.78 liters) of gasoline with 2.6 fluid ounces (77 ml) of oil.
- 5 liters of gasoline with 100 ml of oil.
Always mix the fuel and oil in a clean, approved fuel container. Shake the container thoroughly to ensure the oil is evenly distributed before pouring it into the chainsaw’s fuel tank.
Checking and Preparing the Chainsaw
Several checks should be performed before attempting to start the chainsaw.
Chain Tensioning
Proper Stihl MS250 chain tensioning is vital for safe and efficient operation. A loose chain can fly off the bar, causing injury, while an overly tight chain can cause excessive wear.
- Check: With the engine off and cool, use your gloved hand to pull the chain around the guide bar. It should move freely and be snug against the bar. There should be no slack.
- Adjust: Locate the chain tensioning screw, usually found near the clutch cover.
- Turn the screw clockwise to tighten the chain.
- Turn the counter-clockwise to loosen it.
- Periodically check and adjust as needed, especially when the chain is new or after prolonged use.
Guide Bar and Chain Inspection
- Inspect the guide bar for any signs of wear, damage, or burrs. Ensure the groove is clean.
- Check the chain for dull or damaged cutters. A sharp chain cuts efficiently and reduces engine strain.
Air Filter
A clean air filter ensures proper airflow to the engine. A clogged filter can make starting difficult and reduce performance.
- Locate the air filter cover.
- Remove the cover and inspect the air filter.
- If it’s dirty, you can tap it gently to remove loose debris. For heavy contamination, wash it with warm, soapy water, rinse, and let it dry completely before reinstalling. In some cases, replacement might be necessary.
Spark Arrestor Screen
The spark arrestor screen in the muffler prevents hot sparks from escaping, reducing the risk of fires. If this screen becomes clogged with carbon, it can hinder starting.
- Allow the chainsaw to cool completely.
- Remove the muffler cover (if applicable) and the spark arrestor screen.
- Clean the screen with a wire brush. If it’s damaged or excessively clogged, it should be replaced.
The Stihl MS250 Starting Procedure: Step-by-Step
Now that your chainsaw is prepared, let’s go through the specific Stihl MS250 starting procedure. Always operate in a well-ventilated area, away from flammable materials.
Step 1: Safety First – Stihl MS250 Safety Tips
Before starting, ensure you are adhering to all Stihl MS250 safety tips.
- Protective Gear: Always wear appropriate personal protective equipment (PPE), including:
- Safety glasses or a face shield.
- Hearing protection.
- Cut-resistant gloves.
- Chainsaw chaps or trousers.
- Steel-toed boots.
- Clear Area: Ensure the cutting area is clear of obstacles, people, and animals.
- Stable Footing: Position yourself with stable footing. Avoid starting the chainsaw on a slippery surface or while holding it in the air.
- Guide Bar: Ensure the guide bar is clear of any obstructions and the chain brake is engaged (pulled forward towards the front handle) before you start.
Step 2: Engage the Chain Brake
Always ensure the chain brake is engaged by pushing the front handguard forward until it clicks. This prevents the chain from moving unexpectedly when the engine starts.
Step 3: Set the Choke
The choke is essential for starting a cold engine. It enriches the fuel-air mixture.
- Locate the choke lever. It’s usually a small lever near the air filter cover.
- For a cold start, move the choke lever to the “closed” or “choke” position (typically indicated by a symbol or the lever being pushed in).
- For a warm start (if the engine has recently been running), leave the choke in the “open” or “run” position (lever pushed out).
Step 4: Set the Throttle Lock (If Applicable)
Some MS250 models have a throttle lock feature. If yours does, engage it to hold the throttle open slightly when the choke is on. This helps the engine run at a slightly higher idle for easier starting.
Step 5: Prime the Engine (If Equipped)
Many modern Stihl chainsaws, including the MS250, have a primer bulb.
- Locate the primer bulb, usually a small, clear rubber dome on the side of the engine housing.
- Press the primer bulb repeatedly (usually 3-5 times) until you see fuel return to the bulb. This helps draw fuel into the carburetor.
Step 6: Pull the Starter Rope
This is the core of the Stihl MS250 starting procedure.
- Place the chainsaw on a firm, flat surface.
- Place your left foot through the rear handle or firmly on the rear handle to stabilize the unit.
- Grip the starter rope handle firmly with your right hand.
- Pull the starter rope steadily and smoothly until you feel resistance. Then, give it a sharp, quick pull.
- For a cold start with the choke on: You should hear the engine sputter or attempt to fire. This indicates it’s ready for the next step.
- For a warm start with the choke off: You may need to pull the rope a few times to get it to start.
Step 7: Adjust the Choke (After Sputtering)
If you heard the engine sputter on a cold start with the choke engaged:
- Move the choke lever to the “open” or “run” position.
- If you engaged the throttle lock, release it.
- Give the starter rope another quick pull. The engine should now start and run.
Step 8: Allow the Engine to Warm Up
Once the engine starts and is running:
- Let the engine idle for a few seconds.
- You can gently squeeze the throttle trigger to increase the RPMs slightly to help it warm up and clear any remaining fuel from the choke circuit.
- Do NOT immediately engage the throttle fully or start cutting.
Step 9: Disengage the Chain Brake
When the engine is running smoothly and warmed up:
- Push the front handguard (chain brake) forward again. This disengages the brake, allowing the chain to spin.
Step 10: Check Chain Oil Flow
Before cutting, it’s important to verify that the chain oiler is working.
- Point the tip of the guide bar at a light-colored surface (like a piece of cardboard or a log).
- Briefly squeeze the throttle.
- You should see a thin line of oil being thrown off the chain. If not, refer to troubleshooting.
Your Stihl MS250 is now ready for use!
Essential Stihl MS250 Maintenance
Regular Stihl MS250 maintenance will ensure your chainsaw starts easily and performs reliably for years.
Routine Checks
- After each use:
- Clean the exterior of the chainsaw.
- Check chain tension and adjust if necessary.
- Inspect the guide bar and chain for damage.
- Check the air filter.
- Periodically:
- Clean or replace the spark plug.
- Inspect the muffler and spark arrestor screen.
- Check the clutch and sprocket for wear.
Stihl MS250 Assembly
If you’ve recently purchased your MS250 or replaced the guide bar and chain, you’ll need to perform basic Stihl MS250 assembly.
- Attach Guide Bar and Chain:
- Remove the clutch cover.
- Place the guide bar onto the mounting studs, ensuring the oiler hole aligns with the oiler nipple on the saw body.
- Place the chain onto the guide bar, ensuring the cutters are facing the correct direction (forward on the top of the bar).
- Engage the chain tensioning screw until there’s just enough slack to loop the chain around the sprocket.
- Tighten the chain tensioning screw until the chain is snug against the bar.
- Reinstall the clutch cover and tighten the nuts.
- Adjust chain tension again as described earlier.
Stihl MS250 Carburetor Adjustment
While modern chainsaws often have factory-set carburetors, you might occasionally need Stihl MS250 carburetor adjustment, especially if the engine runs rough, stalls, or won’t idle properly. This is a delicate process best left to those comfortable with small engine mechanics, or performed by a qualified service center.
- Locate Adjustment Screws: Most carburetors have three screws:
- Idle Speed Screw (LS or LA): Adjusts the engine speed when the throttle is not engaged.
- High-Speed (HS) and Low-Speed (LS) Mixture Screws: These control the fuel-air mixture at different throttle settings. For the MS250, these are typically sealed or difficult to access without specialized tools, as they are often factory preset for emission compliance.
- General Procedure (for models with accessible screws):
- Ensure the engine is warm.
- Adjust the idle speed screw to achieve a stable idle.
- (If accessible and necessary) Adjust the low-speed mixture screw to prevent stalling when transitioning from idle to acceleration.
- (If accessible and necessary) Adjust the high-speed mixture screw for optimal performance at full throttle.
- Consult Your Owner’s Manual: The Stihl MS250 owner’s manual will provide specific instructions and diagrams for your model’s carburetor adjustments. Incorrect adjustments can lead to poor performance, engine damage, or increased emissions.
Stihl MS250 Troubleshooting: Common Issues and Solutions
Even with proper care, you might encounter issues. Here’s a look at common Stihl MS250 troubleshooting scenarios.
| Problem | Possible Cause | Solution |
|---|---|---|
| Chainsaw won’t start | Empty fuel tank | Refill with properly mixed fuel. |
| Incorrect fuel mixture | Drain and refill with the correct 50:1 mixture. | |
| Choke set incorrectly (for cold start) | Ensure choke is in the “closed” position for cold starts. | |
| Spark plug fouled or faulty | Remove, clean, and check the spark plug gap. Replace if damaged or old. | |
| Clogged air filter | Clean or replace the air filter. | |
| Spark arrestor screen clogged | Clean the spark arrestor screen. | |
| Carburetor issue (e.g., gummed up) | Clean the carburetor. If issues persist, professional service may be needed. | |
| Chainsaw starts but stalls | Choke not opened after sputtering | Ensure choke is in the “open” position once the engine sputters. |
| Idle speed too low | Adjust the idle speed screw to slightly increase idle RPM. | |
| Fuel/air mixture too lean | Check for air leaks, ensure carburetor is properly adjusted (if applicable), or clean carburetor. | |
| Air filter dirty | Clean or replace the air filter. | |
| Poor cutting performance | Dull chain | Sharpen the chain. |
| Incorrect chain tension | Adjust chain tension (too loose or too tight). | |
| Guide bar worn or damaged | Inspect and potentially replace the guide bar. | |
| Clogged oiler or oil tank empty | Ensure the chain oil tank is full and the oiler is not blocked. Check chain oil flow. | |
| Carburetor not adjusted correctly | Consult a professional for carburetor adjustment. | |
| Excessive vibration | Chain not properly tensioned | Check and adjust chain tension. |
| Dull or damaged chain cutters | Sharpen or replace the chain. | |
| Worn clutch or sprocket | Inspect clutch and sprocket for wear and replace if necessary. | |
| No chain oil flow | Oil tank empty | Refill the chain oil tank. |
| Oiler passage clogged | Clean the oiler passage. Use a fine wire to clear blockages. | |
| Oil pump issue | This usually requires professional service. |
Understanding the Stihl MS250 Parts Diagram
When performing maintenance or repairs, having a Stihl MS250 parts diagram is incredibly useful. This diagram visually labels all the components of your chainsaw, helping you identify specific parts for replacement or inspection. You can typically find this diagram in your Stihl MS250 owner’s manual or on Stihl’s official website.
Frequently Asked Questions (FAQ)
Here are answers to some common questions about starting and maintaining your Stihl MS250.
What is the correct Stihl MS250 fuel mixture?
The correct Stihl MS250 fuel mixture is 50:1, meaning 50 parts gasoline to 1 part high-quality two-stroke engine oil. Always use fresh, unleaded gasoline and Stihl two-stroke oil or an equivalent.
How do I know if my Stihl MS250 needs carburetor adjustment?
Signs that your Stihl MS250 carburetor adjustment might be needed include the chainsaw stalling when you release the throttle, running rough at idle, having difficulty accelerating, or running poorly at high speeds. It’s best to consult your owner’s manual or a professional if you suspect carburetor issues.
Can I use regular gasoline in my Stihl MS250?
You must use unleaded gasoline with an octane rating of 89 or higher. Never use leaded gasoline. It’s also recommended to use ethanol-free gasoline if available to prevent potential fuel system issues.
How often should I check my Stihl MS250 chain tensioning?
You should check Stihl MS250 chain tensioning before each use and adjust it as needed. Chains can stretch or tighten due to heat, so it’s crucial to ensure it’s always at the correct tension.
What should I do if my Stihl MS250 won’t start?
Refer to the Stihl MS250 troubleshooting section of this guide. Common culprits include an empty fuel tank, incorrect fuel mixture, fouled spark plug, or a clogged air filter.
Where can I find my Stihl MS250 owner’s manual?
Your Stihl MS250 owner’s manual is usually included with your chainsaw at the time of purchase. If you’ve lost it, you can typically download a digital copy from the official Stihl website by searching for your specific model number.
Is it okay to start the chainsaw without engaging the chain brake?
No, absolutely not. Always ensure the chain brake is engaged (pushed forward) before initiating the Stihl MS250 starting procedure to prevent accidental chain movement and injury.
By following these detailed steps and maintenance guidelines, you can confidently start your Stihl MS250 chainsaw and keep it running in optimal condition for all your cutting needs. Remember, safety is always the top priority.