Starting a Stihl MS250: Essential Steps for Reliable Ignition (5 Pro Hacks)

The Stihl MS250: A Versatile Workhorse

I’ve always believed that the true measure of a chainsaw isn’t just its power, but its versatility. Over the years, I’ve seen chainsaws come and go, each promising the moon, but few delivering the kind of consistent, reliable performance that makes a real difference when you’re out in the field. That’s why I’ve always had a soft spot for the Stihl MS250. It’s not the biggest or the baddest saw out there, but it’s a dependable workhorse that can handle a wide range of tasks, from limbing and felling small trees to bucking firewood.

The Stihl MS250 is a champion of versatility. Its balanced design and manageable weight make it easy to maneuver, while its powerful engine provides enough grunt to tackle most common wood-cutting jobs. It’s the kind of saw that you can rely on day in and day out, whether you’re a homeowner cleaning up after a storm or a seasoned pro cutting firewood for the winter.

But even the most reliable tools need a little TLC, and the MS250 is no exception. One of the most common issues I’ve seen with these saws is starting problems, especially when they’ve been sitting idle for a while. That’s why I’ve put together this guide to help you get your Stihl MS250 roaring to life every time. I’ll share some essential steps and pro hacks that I’ve learned over the years to ensure reliable ignition and keep your saw running smoothly. So, let’s dive in and get your saw ready to tackle any wood-cutting challenge that comes your way.

Starting a Stihl MS250: Essential Steps for Reliable Ignition (5 Pro Hacks)

Getting a chainsaw started can sometimes feel like a battle of wills, especially when the engine refuses to cooperate. Over the years, I’ve faced my fair share of stubborn saws, and I’ve learned that a systematic approach is key to success. Here are the essential steps I follow to start a Stihl MS250 reliably, along with some pro hacks to tackle common ignition issues.

Step 1: Fuel and Oil Check – The Foundation of a Healthy Engine

Before you even think about pulling the starter cord, make sure your saw has the fuel and oil it needs to run properly. This might seem obvious, but it’s surprising how often this simple step is overlooked.

• Fuel: The Stihl MS250, like most two-stroke engines, requires a mix of gasoline and two-stroke oil. The correct ratio is crucial for proper lubrication and engine performance. Stihl recommends a 50:1 mix, which means 50 parts gasoline to 1 part two-stroke oil. I always use a high-quality, synthetic two-stroke oil to ensure optimal engine protection.

  • Pro Tip: I always pre-mix my fuel in a separate container to ensure the correct ratio. It’s also a good idea to use fresh fuel. Gasoline can degrade over time, especially if it contains ethanol, which can absorb moisture and cause starting problems. I avoid using fuel that’s been sitting around for more than a month or two.

  • Chain Oil: Don’t forget to check the chain oil level as well. The chain oil lubricates the chain and bar, preventing excessive wear and heat buildup. A dry chain can quickly damage the bar and chain, and it can also be a safety hazard.

  • Pro Tip: I prefer to use a high-quality bar and chain oil specifically designed for chainsaws. These oils often contain additives that help reduce wear and improve lubrication. Also, I regularly check the oiler to make sure it’s working properly. A simple way to do this is to hold the saw over a piece of cardboard and rev the engine. You should see a stream of oil being ejected from the chain.

Step 2: Master Control – Setting the Stage for Ignition

The master control lever on the Stihl MS250 controls the choke and the on/off switch. Proper positioning of this lever is essential for starting the saw.

• Cold Start: When starting a cold engine, move the master control lever all the way down to the “choke” position. This will close the choke, which restricts airflow to the carburetor, creating a richer fuel mixture that’s easier to ignite.
• Warm Start: If the engine is already warm, move the master control lever to the “run” position (one position up from the bottom). This will open the choke and allow the engine to breathe freely.

• On/Off Switch: Make sure the on/off switch is in the “on” position. It’s easy to overlook this simple step, especially if you’re in a hurry.

  • Pro Tip: I always double-check the master control lever and the on/off switch before pulling the starter cord. It’s a simple habit that can save you a lot of frustration.

Step 3: Priming the Carburetor – Ensuring Fuel Delivery

The primer bulb is a small, clear bulb located on the carburetor. Pressing this bulb draws fuel from the fuel tank into the carburetor, making it easier to start the engine.

• Priming Procedure: Press the primer bulb several times (usually 6-8 times) until you see fuel flowing through it. Don’t over-prime the engine, as this can flood the carburetor and make it difficult to start.

• Observing Fuel Flow: Pay attention to the fuel flow in the primer bulb. If you don’t see any fuel flowing, it could indicate a problem with the fuel filter or the fuel line.

  • Pro Tip: I always use a gentle, consistent pressure when priming the carburetor. Avoid squeezing the bulb too hard, as this can damage it.

Step 4: Starting the Engine – The Moment of Truth

Now comes the moment of truth: pulling the starter cord. Here’s how to do it properly:

• Foot Placement: Place the saw on a firm, level surface. I usually place my right foot through the rear handle to hold the saw securely.
• Grip and Pull: Grip the starter handle firmly and pull the cord smoothly and steadily. Avoid jerking or yanking the cord, as this can damage the starter mechanism.
• Initial Start: With the choke engaged (master control lever all the way down), pull the starter cord until the engine sputters or tries to start. This usually takes a few pulls.
• Warm-Up: Once the engine sputters, move the master control lever to the “run” position (one position up from the bottom) and continue pulling the starter cord until the engine starts and runs smoothly.

• Idle Adjustment: Let the engine warm up for a minute or two before engaging the chain. If the engine idles too fast or too slow, you can adjust the idle speed screw on the carburetor.

  • Pro Tip: I always use a smooth, controlled motion when pulling the starter cord. Avoid pulling the cord all the way out, as this can damage the recoil mechanism. Also, I never release the starter handle abruptly. Always let it retract slowly to prevent damage.

Step 5: Troubleshooting – When Things Don’t Go According to Plan

Sometimes, despite your best efforts, the engine just won’t start. Here are some common troubleshooting tips:

• Flooded Engine: If the engine is flooded (you can smell gasoline), move the master control lever to the “run” position and pull the starter cord several times to clear the excess fuel. You may need to remove the spark plug and dry it off as well.
• Spark Plug Issues: A fouled or damaged spark plug can prevent the engine from starting. Remove the spark plug and inspect it for signs of damage or carbon buildup. Clean the spark plug with a wire brush or replace it with a new one. The gap should be 0.5mm.
• Fuel Filter Problems: A clogged fuel filter can restrict fuel flow to the carburetor. Remove the fuel filter from the fuel tank and inspect it for debris. Clean the filter or replace it with a new one.
• Air Filter Problems: A dirty air filter can restrict airflow to the engine. Remove the air filter and inspect it for dirt and debris. Clean the filter with soap and water or replace it with a new one.

• Ignition Coil Issues: A faulty ignition coil can prevent the spark plug from firing. This is a more complex issue that may require professional repair.

  • Pro Tip: I always keep a spare spark plug, fuel filter, and air filter on hand for quick repairs in the field. It’s also a good idea to have a basic understanding of chainsaw mechanics so you can diagnose and fix common problems yourself.

5 Pro Hacks for Reliable Ignition

Now that we’ve covered the essential steps for starting a Stihl MS250, let’s dive into some pro hacks that can help you achieve reliable ignition every time. These are the tips and tricks I’ve learned over the years from seasoned loggers and chainsaw mechanics.

Hack #1: The “Burp” Technique – Clearing Excess Fuel

One of the most common causes of starting problems is a flooded engine. This happens when too much fuel enters the carburetor, making it difficult for the engine to ignite. The “burp” technique is a simple way to clear excess fuel from the cylinder.

• Procedure: Remove the spark plug and turn the saw upside down. Pull the starter cord several times to expel any excess fuel from the cylinder. Replace the spark plug and try starting the engine again.

  • Why it Works: Turning the saw upside down allows gravity to help drain the excess fuel from the cylinder. Pulling the starter cord then forces the fuel out through the spark plug hole.
  • My Experience: I remember one time I was cutting firewood in the dead of winter, and my MS250 just wouldn’t start. I tried everything, but the engine was completely flooded. I was about to give up when an old logger showed me the “burp” technique. I tried it, and to my surprise, the saw started right up. I’ve been using this trick ever since.

Hack #2: The “Heat Gun” Trick – Warming Up a Cold Engine

In cold weather, it can be difficult to start a chainsaw because the fuel doesn’t vaporize as easily. The “heat gun” trick can help warm up the engine and improve fuel vaporization.

• Procedure: Use a heat gun to gently warm up the carburetor and cylinder area. Be careful not to overheat the engine, as this can damage it. Try starting the engine again.

  • Why it Works: Warming up the engine helps the fuel vaporize more easily, creating a more combustible mixture.
  • My Experience: I’ve used this trick many times when cutting firewood in sub-zero temperatures. It can make a huge difference in starting performance. Just be sure to use a low setting on the heat gun and avoid focusing the heat on any one spot for too long.

Hack #3: The “Spark Test” – Verifying Ignition System Functionality

If you suspect a problem with the ignition system, you can perform a simple spark test to verify that the spark plug is firing properly.

• Procedure: Remove the spark plug and reattach it to the spark plug wire. Hold the spark plug against a metal part of the engine (such as the cylinder head) and pull the starter cord. You should see a bright blue spark jumping across the spark plug gap. If you don’t see a spark, it could indicate a problem with the ignition coil, spark plug wire, or spark plug.

  • Why it Works: This test verifies that the ignition system is generating enough voltage to create a spark at the spark plug.
  • My Experience: I once had a Stihl MS250 that wouldn’t start, and I suspected a problem with the ignition system. I performed the spark test and found that there was no spark at all. After replacing the ignition coil, the saw started right up.

Hack #4: The “Carb Cleaner” Solution – Clearing Carburetor Passages

Over time, carburetor passages can become clogged with varnish and debris, restricting fuel flow and causing starting problems. Carb cleaner can help dissolve these deposits and restore proper fuel flow.

• Procedure: Remove the air filter and spray carb cleaner directly into the carburetor throat. Let the carb cleaner sit for a few minutes to dissolve the deposits. Try starting the engine again. You may need to repeat this process several times.

  • Why it Works: Carb cleaner contains solvents that dissolve varnish and debris, clearing the carburetor passages and restoring proper fuel flow.
  • My Experience: I’ve used carb cleaner many times to revive old chainsaws that have been sitting idle for a long time. It’s a simple and effective way to clean the carburetor without having to disassemble it.

Hack #5: The “Compression Check” – Assessing Engine Health

Low compression can make it difficult to start a chainsaw and can also indicate serious engine problems. A compression check can help you assess the overall health of the engine.

• Procedure: Remove the spark plug and screw a compression tester into the spark plug hole. Pull the starter cord several times and note the reading on the compression tester. A healthy Stihl MS250 should have a compression reading of at least 120 PSI.

  • Why it Works: A compression test measures the pressure inside the cylinder when the piston is at the top of its stroke. Low compression can indicate worn piston rings, damaged cylinder walls, or leaky valves.
  • My Experience: I once bought a used Stihl MS250 that was difficult to start. I performed a compression check and found that the compression was only 90 PSI. This indicated that the engine was worn and needed to be rebuilt.

Maintaining Your Stihl MS250 for Long-Term Reliability

Starting your Stihl MS250 is just the first step. To ensure long-term reliability and performance, it’s essential to perform regular maintenance. Here are some key maintenance tasks:

• Air Filter Cleaning: Clean the air filter regularly (every 5-10 hours of use) to prevent dirt and debris from entering the engine.
• Spark Plug Replacement: Replace the spark plug annually or after every 100 hours of use.
• Fuel Filter Replacement: Replace the fuel filter annually or whenever it appears clogged.
• Chain Sharpening: Sharpen the chain regularly to maintain optimal cutting performance. A dull chain can be dangerous and can also put unnecessary strain on the engine.
• Bar Maintenance: Clean the bar regularly and check for wear and damage. Lubricate the bar sprocket to ensure smooth chain movement.
• Carburetor Adjustment: Adjust the carburetor as needed to maintain proper fuel mixture and idle speed.
• Storage: When storing the saw for extended periods, drain the fuel tank and run the engine until it stalls. This will prevent fuel from degrading and clogging the carburetor.

Wood Species and Processing Techniques

The type of wood you’re cutting can also affect the performance of your chainsaw. Different wood species have different densities and hardness, which can impact cutting speed and chain wear.

• Softwoods: Softwoods, such as pine, fir, and spruce, are generally easier to cut than hardwoods. They also tend to be less abrasive, which means they’re less likely to dull the chain.
• Hardwoods: Hardwoods, such as oak, maple, and hickory, are denser and harder than softwoods. They require more power to cut and can dull the chain more quickly.

When processing wood, it’s important to use the right techniques to ensure safety and efficiency.

• Felling: When felling a tree, always assess the lean of the tree and plan your escape route. Use proper felling techniques to control the direction of the fall.
• Limbing: When limbing a tree, work from the base towards the top, removing the branches one at a time. Be careful to avoid kickback.
• Bucking: When bucking a log into firewood, support the log properly to prevent it from pinching the chain. Use proper bucking techniques to avoid kickback and maintain control of the saw.

Safety First: Protecting Yourself and Others

Chainsaw operation can be dangerous if proper safety precautions are not followed. Always wear appropriate personal protective equipment (PPE), including:

• Eye Protection: Wear safety glasses or a face shield to protect your eyes from flying debris.
• Hearing Protection: Wear earplugs or earmuffs to protect your hearing from the loud noise of the chainsaw.
• Head Protection: Wear a hard hat to protect your head from falling branches and other hazards.
• Hand Protection: Wear chainsaw gloves to protect your hands from cuts and vibrations.
• Leg Protection: Wear chainsaw chaps or pants to protect your legs from cuts.
• Foot Protection: Wear steel-toed boots to protect your feet from falling logs and other hazards.

In addition to wearing proper PPE, it’s important to follow these safety guidelines:

• Read the Owner’s Manual: Familiarize yourself with the chainsaw’s operating instructions and safety precautions.
• Inspect the Saw: Before each use, inspect the saw for any signs of damage or wear.
• Maintain a Safe Distance: Keep bystanders at least 50 feet away from the work area.
• Avoid Cutting Overhead: Avoid cutting branches that are directly overhead.
• Be Aware of Kickback: Understand the causes of kickback and take steps to prevent it.
• Never Cut Above Shoulder Height: Cutting above shoulder height can be dangerous and can lead to loss of control.
• Take Breaks: Take frequent breaks to avoid fatigue, which can increase the risk of accidents.

The Stihl MS250: A Trusted Companion

The Stihl MS250 has been a trusted companion for me for many years. Its versatility, reliability, and ease of use make it an excellent choice for a wide range of wood-cutting tasks. By following the essential steps and pro hacks outlined in this guide, you can ensure reliable ignition and keep your MS250 running smoothly for years to come. Always remember to prioritize safety and perform regular maintenance to protect yourself and your equipment. With a little care and attention, your Stihl MS250 will be a valuable tool for all your wood-cutting needs.

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