Stihl MS250 18 Inch Replacement Chain Guide (5 Pro Tips Inside)

I believe in a world where we can heat our homes and power our lives without compromising the health of our planet. That’s why I’m so passionate about sustainable wood processing and responsible firewood preparation. One of the most crucial aspects of this is maintaining our tools properly, ensuring they run efficiently and safely.

If you’re reading this, you likely own or are considering owning a Stihl MS250. It’s a popular choice for good reason – it’s reliable, powerful, and relatively easy to maintain. But like any chainsaw, the chain and guide bar are wear items, and eventually, you’ll need to replace them. Choosing the right replacement chain and guide bar is crucial for optimal performance, safety, and longevity of your saw.

In this guide, I’m going to share my in-depth knowledge and hands-on experience with the Stihl MS250, focusing specifically on selecting the perfect 18-inch replacement chain and guide bar. I’ve spent countless hours felling trees, bucking logs, and processing firewood, and I’ve learned a thing or two about what works and what doesn’t.

Key Takeaways You’ll Discover:

Understanding Chain Types: Learn the differences between various chain types (full chisel, semi-chisel, low-profile) and which is best for your needs.
Guide Bar Selection: Discover the importance of matching the correct guide bar with your chain and saw.
Tensioning Techniques: Master the art of proper chain tensioning for optimal cutting and safety.
Maintenance Matters: Understand how to extend the life of your chain and guide bar through regular maintenance.
Troubleshooting Tips: Identify and address common issues like chain slippage, dull cutting, and bar wear.

Let’s dive in and unlock the secrets to keeping your Stihl MS250 running like a champ!

The Stihl MS250: A Chainsaw Champion

The Stihl MS250 is a mid-range chainsaw that has earned a reputation for being a reliable and versatile tool. It’s popular among homeowners, farmers, and even some professionals for its power, ease of use, and relatively lightweight design.

Engine Specs: Typically powered by a 45.4 cc engine, the MS250 provides ample power for felling small to medium-sized trees, limbing, and cutting firewood.
Weight: Weighing in around 10.1 pounds (without the bar and chain), it’s manageable for extended use without excessive fatigue.
Common Uses: Ideal for property maintenance, storm cleanup, and preparing firewood for the winter.

Many users, including myself, have found the MS250 to be a great all-around chainsaw. I remember one particular instance where a large storm downed several trees on my property. The MS250, equipped with a sharp chain, made quick work of the cleanup, allowing me to clear the debris and restore order in no time. It’s this kind of reliability that makes it a favorite among chainsaw users.

Understanding Chainsaw Chains: A Deep Dive

The chainsaw chain is the heart of the cutting process. Choosing the right chain is paramount for efficient cutting, safety, and the longevity of your Stihl MS250.

Types of Chainsaw Chains

There are three primary types of chainsaw chains:

Full Chisel Chains: These chains have square-cornered cutters that provide the fastest cutting speed and are ideal for clean wood. However, they are more prone to dulling in dirty or frozen wood. I personally prefer full chisel chains when I’m working with freshly felled timber that’s free of dirt and debris. According to research from Oregon Products, full chisel chains can cut up to 20% faster than semi-chisel chains in optimal conditions.
Semi-Chisel Chains: These chains have rounded cutters that are more durable and forgiving in dirty or frozen wood. They offer a good balance between cutting speed and durability. I often switch to a semi-chisel chain when I know I’ll be cutting wood that might have some embedded dirt or debris.
Low-Profile Chains: Also known as safety chains, these chains have a smaller cutter and a reduced kickback potential. They are often recommended for beginners or users who prioritize safety over cutting speed.

Chain Pitch, Gauge, and Drive Links

Understanding these three terms is crucial for selecting the correct replacement chain for your Stihl MS250.

Pitch: The pitch is the distance between any three consecutive rivets on the chain, divided by two. Common pitches are 3/8″ and .325″. The Stihl MS250 typically uses a .325″ pitch chain.
Gauge: The gauge is the thickness of the drive links, which fit into the groove of the guide bar. The MS250 usually uses a .063″ gauge chain.
Drive Links: The number of drive links is the total number of links that fit into the guide bar groove. For an 18-inch bar on the MS250, you’ll typically need a chain with 74 drive links.

Pro Tip: Always consult your chainsaw’s owner’s manual to confirm the correct pitch, gauge, and drive link count for your specific model and bar length.

Matching the Chain to Your Needs

When selecting a chain, consider the type of wood you’ll be cutting and the conditions you’ll be working in.

Softwoods (Pine, Fir): Full chisel chains work well for cutting softwoods due to their aggressive cutting action.
Hardwoods (Oak, Maple): Semi-chisel chains are a better choice for hardwoods as they are more durable and resistant to dulling.
Dirty or Frozen Wood: Opt for a semi-chisel chain when cutting wood that may contain dirt, debris, or is frozen.

Selecting the Right Guide Bar: A Critical Choice

The guide bar provides the track for the chain to run along and supports the chain during the cutting process. Choosing the correct guide bar is just as important as selecting the right chain.

Guide Bar Length

The length of the guide bar determines the maximum diameter of wood you can cut. For the Stihl MS250, an 18-inch bar is a common and versatile choice. It provides a good balance between maneuverability and cutting capacity.

Important Note: Never use a guide bar that is longer than the maximum recommended length for your chainsaw model. Using an excessively long bar can overload the engine and potentially damage the saw.

Guide Bar Types

There are several types of guide bars available, each with its own advantages and disadvantages:

Laminated Bars: These bars are made from multiple layers of steel welded together. They are lighter and less expensive than solid bars. I’ve found them to be perfectly adequate for most homeowner and light-duty applications.
Solid Bars: These bars are made from a single piece of steel. They are more durable and resistant to bending, making them a better choice for heavy-duty use.
Sprocket Nose Bars: These bars have a replaceable sprocket at the tip, which reduces friction and extends the life of the bar. I personally prefer sprocket nose bars as they tend to cut smoother and require less effort.

Guide Bar Maintenance

Proper guide bar maintenance is essential for extending its life and ensuring optimal performance.

Cleaning: Regularly clean the guide bar groove with a bar groove cleaner to remove sawdust and debris.
Filing: File down any burrs or damage on the bar rails to ensure smooth chain travel.
Lubrication: Ensure the bar is properly lubricated with chain oil to reduce friction and wear.

Pro Tip #1: Mastering Chain Tensioning

Proper chain tension is crucial for safe and efficient cutting. A chain that is too loose can derail, while a chain that is too tight can overheat and damage the bar and chain.

How to Tension Your Chain

Loosen the bar nuts: Use the wrench that came with your chainsaw to slightly loosen the bar nuts.
Adjust the tensioning screw: Locate the chain tensioning screw on the side of the saw. Turn the screw clockwise to tighten the chain and counterclockwise to loosen it.
Check the tension: The chain should be snug against the guide bar, but you should still be able to pull it around the bar by hand. A good rule of thumb is to be able to pull the chain away from the bar about the thickness of a dime.
Tighten the bar nuts: Once the chain is properly tensioned, tighten the bar nuts securely.

Important Note: Always check the chain tension after the first few cuts, as the chain will stretch slightly as it warms up.

Pro Tip #2: Sharpening Your Chain Like a Pro

A sharp chain is essential for efficient cutting and safety. A dull chain requires more force to cut, which can lead to fatigue and increase the risk of kickback.

Tools for Sharpening

Round File: Use a round file of the correct size for your chain’s pitch. For a .325″ pitch chain, a 5/32″ file is typically recommended.
File Guide: A file guide helps you maintain the correct filing angle and depth.
Depth Gauge Tool: Use a depth gauge tool to check and adjust the depth of the rakers (also known as depth gauges or gullets).

Sharpening Technique

Secure the Chain: Secure the chain in a vise or use a chain vise that attaches to the guide bar.
File the Cutters: File each cutter using smooth, even strokes, following the existing angle of the cutter. Use a file guide to maintain the correct angle and depth.
Check the Depth Gauges: Use a depth gauge tool to check the height of the rakers. If they are too high, file them down slightly using a flat file.
Repeat: Repeat the process for all the cutters on the chain.

Expert Insight: According to a study by the Forest Engineering Research Institute of Canada (FERIC), a properly sharpened chain can increase cutting productivity by up to 30%.

Pro Tip #3: The Importance of Chain Oil

Chain oil is essential for lubricating the chain and guide bar, reducing friction, and preventing wear. Using the wrong type of chain oil or neglecting to oil the chain can lead to premature failure of the bar and chain.

Types of Chain Oil

Petroleum-Based Chain Oil: This is the most common type of chain oil and is readily available at most hardware stores.
Vegetable-Based Chain Oil: This type of chain oil is biodegradable and environmentally friendly. I prefer to use vegetable-based chain oil whenever possible to minimize my environmental impact.
Synthetic Chain Oil: Synthetic chain oils offer superior lubrication and performance, especially in extreme temperatures.

Choosing the Right Chain Oil

When selecting chain oil, consider the following factors:

Viscosity: Choose a chain oil with the correct viscosity for the ambient temperature. In colder temperatures, use a thinner oil. In warmer temperatures, use a thicker oil.
Tackiness: Choose a chain oil that is tacky enough to cling to the chain and guide bar, but not so tacky that it attracts excessive dirt and debris.
Environmental Impact: Consider using a vegetable-based chain oil to minimize your environmental impact.

Checking and Filling the Oil Reservoir

Regularly check the oil reservoir and fill it as needed. A good rule of thumb is to refill the oil reservoir every time you refill the fuel tank.

Pro Tip #4: Troubleshooting Common Issues

Even with proper maintenance, you may encounter some common issues with your Stihl MS250 chain and guide bar.

Chain Slippage

Cause: Loose chain tension, worn drive sprocket, or worn chain.
Solution: Adjust the chain tension, replace the drive sprocket, or replace the chain.

Dull Cutting

Cause: Dull chain, incorrect filing angle, or incorrect depth gauge setting.
Solution: Sharpen the chain, correct the filing angle, or adjust the depth gauge setting.

Bar Wear

Cause: Insufficient lubrication, incorrect chain tension, or cutting in dirty conditions.
Solution: Ensure proper lubrication, adjust the chain tension, and avoid cutting in dirty conditions.

Chain Breakage

Cause: Worn chain, excessive force, or hitting a foreign object.
Solution: Replace the chain, avoid applying excessive force, and be careful when cutting near the ground or in areas where there may be hidden objects.

Pro Tip #5: Storing Your Chainsaw for Longevity

Proper storage is crucial for extending the life of your Stihl MS250 and its components.

Cleaning: Thoroughly clean the chainsaw after each use, removing all sawdust and debris.
Draining Fuel: Drain the fuel tank before storing the chainsaw for an extended period. This will prevent the fuel from deteriorating and causing problems.
Oiling the Chain: Lightly oil the chain and guide bar to prevent rust.
Storing in a Dry Place: Store the chainsaw in a dry, well-ventilated place.

Final Thoughts: A Sustainable Approach

Choosing the right replacement chain and guide bar for your Stihl MS250 is a crucial step in ensuring its optimal performance, safety, and longevity. By understanding the different types of chains and bars, mastering proper tensioning and sharpening techniques, and following a regular maintenance schedule, you can keep your chainsaw running smoothly for years to come.

But beyond just tool maintenance, I believe it’s essential to consider the broader context of sustainable wood processing. By using our tools responsibly, sourcing our wood sustainably, and practicing responsible firewood preparation, we can contribute to a healthier planet and ensure that future generations can enjoy the benefits of wood as a renewable resource.

So, get out there, sharpen your skills, and put these pro tips into action. And remember, responsible wood processing is not just about cutting wood; it’s about respecting the environment and ensuring a sustainable future for all. Now that you’re armed with this knowledge, go forth and make some sawdust – responsibly!

Stihl MS250 18 Inch Replacement Chain Guide (5 Pro Tips Inside)

The Stihl MS250: A Chainsaw Champion