How to Change Spark Plug Stihl MS 250: Step-by-Step Tutorial for Beginners and Professionals Alike

The Stihl MS 250 chainsaw is a popular choice for homeowners and professionals alike, known for its power and reliability. However, like any engine, it requires regular maintenance to keep it running smoothly. One of the most important maintenance tasks is changing the spark plug, which is responsible for igniting the fuel-air mixture in the engine.

This blog post will guide you through the process of how to change spark plug Stihl MS 250, providing a step-by-step guide for easy maintenance.

Why Change the Spark Plug?

A spark plug is a vital component in your chainsaw’s engine. It generates the spark that ignites the fuel-air mixture, and over time, it can wear down or become fouled with carbon deposits, affecting performance. Replacing a worn-out spark plug ensures optimal engine performance and prevents potential issues like:

• Difficulty starting: A worn-out spark plug may not generate a strong enough spark to ignite the fuel-air mixture, making it difficult to start the chainsaw.
• Poor acceleration: A fouled spark plug can hinder the engine’s ability to accelerate quickly.
• Rough idling: A worn-out or fouled spark plug can cause the engine to idle unevenly.
• Reduced power: A weakened spark can result in incomplete combustion, leading to a loss of power.
• Increased fuel consumption: An inefficient spark plug can lead to increased fuel consumption.

By changing the spark plug regularly, you can prevent these issues and ensure your Stihl MS 250 chainsaw runs smoothly and efficiently.

What You’ll Need

Before you begin, gather the following tools and materials:

• New spark plug: Use a Stihl-approved spark plug specifically designed for the MS 250. Refer to your owner’s manual for the correct spark plug type.
• Spark plug wrench: This tool is specifically designed to remove and install spark plugs.
• Gloves: Protect your hands from heat and potential cuts.
• Safety glasses: Protect your eyes from debris.
• Clean cloth: For wiping away any dirt or debris.

Step-by-Step Guide to Changing the Spark Plug

Now, let’s get started with the process of changing the spark plug on your Stihl MS 250 chainsaw:

1. Safety First: Always disconnect the spark plug wire from the spark plug before working on the engine. This will prevent accidental ignition and potential injury.

2. Locate the Spark Plug: The spark plug is located on the top of the engine cylinder, behind the air filter housing. It’s usually covered by a small metal cap.

3. Remove the Spark Plug Cap: Carefully remove the spark plug cap by pulling it straight up.

4. Remove the Spark Plug: Use a spark plug wrench to loosen and remove the spark plug. Turn the wrench counterclockwise to loosen it.

5. Inspect the Spark Plug: Examine the old spark plug for signs of wear and tear, such as carbon deposits, electrode erosion, or cracks.

6. Install the New Spark Plug: Thread the new spark plug into the cylinder head by hand until it is snug. Do not overtighten.

7. Tighten the Spark Plug: Use the spark plug wrench to tighten the spark plug. Turn the wrench clockwise until it is snug, but do not overtighten. You can use a torque wrench for precise tightening if available.

8. Reconnect the Spark Plug Wire: Carefully reconnect the spark plug wire to the new spark plug. Ensure it is securely connected.

9. Start the Engine: Start the engine and check for any issues. If the engine starts and runs smoothly, you’ve successfully changed the spark plug.

Tips for Successful Spark Plug Replacement

Here are some helpful tips for a smooth spark plug replacement:

• Clean the Area: Before removing the spark plug, clean the area around it with a clean cloth to prevent dirt and debris from falling into the cylinder.
• Use the Right Wrench: Make sure you use the correct spark plug wrench size for your Stihl MS 250.
• Avoid Overtightening: Overtightening the spark plug can damage the threads in the cylinder head.
• Check the Gap: If you’re familiar with spark plug gap adjustment, ensure the new spark plug’s gap is set correctly according to the manufacturer’s specifications.

Maintaining Your Chainsaw’s Health

Changing the spark plug is just one part of maintaining your Stihl MS 250 chainsaw. Here are other essential maintenance tasks:

• Regularly clean the air filter: A clean air filter ensures optimal engine performance.
• Change the fuel filter: A dirty fuel filter can restrict fuel flow and affect engine performance.
• Check the chain tension: Proper chain tension is essential for safe and efficient cutting.
• Sharpen the chain: A sharp chain cuts more efficiently and reduces the risk of kickback.

Final Thoughts: Keeping Your Chainsaw in Top Shape

By following these simple steps and incorporating regular maintenance, you can ensure your Stihl MS 250 chainsaw continues to perform at its best. A well-maintained chainsaw not only delivers optimal performance but also promotes safety and longevity.

What People Want to Know

Q: How often should I change the spark plug on my Stihl MS 250?

A: It’s recommended to change the spark plug every 50 hours of operation or annually, whichever comes first. However, if you notice any issues like difficulty starting, poor acceleration, or rough idling, you may need to replace the spark plug sooner.

Q: What type of spark plug should I use for my Stihl MS 250?

A: Refer to your owner’s manual for the specific spark plug type recommended for your Stihl MS 250. Using the correct type is crucial for optimal performance and engine longevity.

Q: Can I adjust the spark plug gap myself?

A: If you have experience with spark plug gap adjustment, you can use a spark plug gap tool to adjust the gap according to the manufacturer’s specifications. However, if you’re unsure, it’s best to consult a qualified mechanic.

Q: Is it safe to change the spark plug myself?

A: With proper safety precautions and a basic understanding of the process, changing the spark plug on your Stihl MS 250 is a relatively safe task. However, if you’re not comfortable with the procedure, it’s best to seek professional help.