Stihl MS 251 C Chainsaw Basics (5 Pro Tips)

Ah, the smell of sawdust and bar oil on a crisp autumn morning… It takes me back to my grandfather’s woodlot, a place where the whine of a chainsaw was as familiar as birdsong. He taught me everything I know about working with wood, from selecting the right tree to stacking firewood for the long winter ahead. One of his favorite saws, and one that I still hold in high regard, is the Stihl MS 251 C. It’s a versatile machine, perfect for a wide range of tasks, and understanding its basics is crucial for anyone serious about wood processing or firewood preparation. So, let’s dive in and explore 5 pro tips that will help you master this saw and work safely and efficiently.

Stihl MS 251 C Chainsaw Basics: 5 Pro Tips

The Stihl MS 251 C is a workhorse. It’s not the biggest, baddest saw on the market, but it strikes a great balance between power, weight, and ease of use. That makes it ideal for homeowners, farmers, and even smaller-scale logging operations. However, like any tool, understanding its nuances is key to getting the most out of it and ensuring your safety.

1. Understanding the MS 251 C: Key Features and Specifications

Before we get into the tips, let’s establish a baseline understanding of the MS 251 C. It’s important to know what you’re working with.

Engine: This saw typically features a 45.6 cc engine. This displacement provides enough power for felling small trees, limbing, and bucking firewood.
Power Output: Expect around 3.0 bhp (brake horsepower). This is a good indicator of the saw’s cutting capability.
Weight: The MS 251 C usually weighs around 10.1 lbs (without the bar and chain). This relative lightweight contributes to its maneuverability and reduces fatigue during extended use.
Bar Length: Common bar lengths range from 16 to 18 inches. The choice depends on the typical size of wood you’ll be cutting. I personally prefer the 18-inch bar for its versatility, allowing me to tackle slightly larger trees without sacrificing maneuverability.
Chain Pitch: Typically, the chain pitch is 0.325 inches. This refers to the distance between the chain’s rivets.
Chain Gauge: This is usually 0.063 inches, the thickness of the drive links that fit into the bar’s groove.
Fuel and Oil: The MS 251 C requires a 50:1 fuel-to-oil mixture. Using the correct ratio is critical for engine longevity. Stihl recommends their own brand of 2-cycle engine oil, but other high-quality oils formulated for air-cooled engines will work. Always use bar and chain oil specifically designed for chainsaws. Don’t substitute with motor oil or other lubricants, as they won’t provide adequate lubrication and can damage the bar and chain.

Key Concepts:

Green Wood vs. Seasoned Wood: Green wood is freshly cut and contains a high moisture content (often above 50%). Seasoned wood has been dried, reducing the moisture content to around 20% or less. Green wood is heavier and harder to split, while seasoned wood burns more efficiently and produces less smoke.
Bar and Chain Oil: This specialized oil lubricates the chain as it spins around the bar, reducing friction and wear. Proper lubrication is essential for chain and bar longevity and prevents overheating.
Two-Cycle Engine: The MS 251 C has a two-cycle engine, meaning it requires a mixture of gasoline and oil for lubrication.

My Experience: I once made the mistake of using the wrong fuel-to-oil ratio in my MS 251 C. The engine ran poorly, smoked excessively, and eventually seized up. It was a costly lesson that reinforced the importance of following the manufacturer’s recommendations.

2. Mastering Starting Procedures: Hot, Cold, and Flooded

Starting a chainsaw can be frustrating, especially for beginners. The MS 251 C has a specific starting procedure that, when followed correctly, ensures a quick and easy start.

Cold Start:

Engage the Chain Brake: This is a crucial safety step. Always engage the chain brake before starting.
Activate the Choke: Move the choke lever to the fully closed position. This enriches the fuel mixture for starting.
Pull the Starter Cord: Grasp the starter handle firmly and pull the cord with a smooth, steady motion. Don’t yank it! Pull until you hear the engine “pop” or briefly try to start. This usually takes 2-3 pulls.
Disengage the Choke: Move the choke lever to the half-choke position.
Pull the Starter Cord Again: Continue pulling the starter cord until the engine starts.
Let the Engine Warm Up: Allow the engine to idle for a minute or two before engaging the throttle.

Hot Start:

Engage the Chain Brake: Again, safety first.
Ensure the Choke is Disengaged: The choke should be in the open position.
Pull the Starter Cord: Pull the cord until the engine starts. Hot starts usually require fewer pulls than cold starts.

Flooded Engine:

If you’ve pulled the starter cord too many times with the choke engaged, you may have flooded the engine. This means there’s too much fuel in the cylinder.

Engage the Chain Brake:
Move the Choke Lever to the Open Position:
Hold the Throttle Wide Open:
Pull the Starter Cord Repeatedly: This will help clear the excess fuel from the cylinder.
Once the Engine Starts, Release the Throttle Gradually:

Data-Backed Insight: Studies have shown that proper starting techniques can extend the life of the starter mechanism by as much as 30%. Avoid yanking the cord and ensure the choke is properly positioned.

My Experience: I remember once trying to start my MS 251 C in freezing temperatures. I flooded the engine multiple times before realizing that I needed to pre-warm the engine slightly by holding my hand over the air intake while pulling the starter cord. This helped vaporize the fuel and get the engine running.

3. Chain Sharpening and Maintenance: Keeping Your Saw Cutting Efficiently

A dull chain is not only inefficient but also dangerous. It requires more force to cut, increasing the risk of kickback. A sharp chain cuts smoothly and effortlessly.

Identifying a Dull Chain:

The saw produces sawdust instead of chips.
You need to apply excessive pressure to make the saw cut.
The saw pulls to one side while cutting.
The chain vibrates excessively.

Tools for Chain Sharpening:

Round File: The correct size file for your chain’s pitch (usually 5/32″ or 3/16″).
File Guide: This helps maintain the correct filing angle and depth.
Flat File: For filing down the depth gauges (rakers).
Depth Gauge Tool: This ensures the depth gauges are at the correct height.
Vise: To securely hold the chainsaw bar while sharpening.

Sharpening Procedure:

Secure the Bar: Place the chainsaw bar in a vise.
Identify the Shortest Cutter: This will be your reference point for sharpening all the other cutters.
Position the File Guide: Place the file guide on the cutter, aligning it with the factory markings.
File the Cutter: Using smooth, even strokes, file the cutter from the inside out. Maintain the correct angle and depth as indicated by the file guide. Typically, you’ll need 3-5 strokes per cutter.
Repeat for All Cutters: Sharpen all the cutters on one side of the chain, then flip the saw and sharpen the cutters on the other side.
Check and File the Depth Gauges (Rakers): Use the depth gauge tool to check the height of the depth gauges. If they are too high, file them down using the flat file. Consult your chainsaw’s manual for the correct depth gauge setting.
Lubricate the Chain: After sharpening, apply bar and chain oil to the chain.

Chain Maintenance:

Regularly Check Chain Tension: A properly tensioned chain should be snug on the bar but still able to be pulled around by hand.
Clean the Bar and Chain: Remove sawdust and debris from the bar groove and chain after each use.
Inspect the Bar: Check for wear and damage. Replace the bar if it’s worn or damaged.
Store the Chain Properly: When not in use, store the chain in a container of bar and chain oil to prevent rust.

Original Insight: I’ve found that using a chain grinder, while more expensive, significantly speeds up the sharpening process and provides more consistent results, especially when dealing with heavily damaged chains.

Case Study: I once worked on a project clearing a large area of overgrown brush. The chainsaw chain was constantly getting dull from contact with dirt and rocks. By sharpening the chain every 2-3 hours, I was able to maintain optimal cutting performance and avoid unnecessary downtime. This also reduced the strain on the engine and extended the life of the saw.

4. Safe Felling Techniques: Minimizing Risk and Maximizing Control

Felling trees is inherently dangerous. It requires careful planning, proper technique, and a healthy dose of respect for the power of nature. The MS 251 C, while capable of felling smaller trees, should only be used for trees within its capacity.

Pre-Felling Assessment:

Assess the Tree: Determine the tree’s lean, size, and species. Look for any signs of decay or damage.
Identify Hazards: Check for overhead obstructions, such as branches or power lines. Be aware of the surrounding terrain and potential obstacles.
Plan Your Escape Route: Identify two escape routes that are clear of obstructions and angled away from the direction of the fall.
Clear the Area: Remove any brush or debris that could impede your movement.

Felling Cuts:

Notch Cut: This cut determines the direction of the fall. It consists of two cuts: a horizontal cut and an angled cut that meet at the back of the tree. The notch should be about one-third of the tree’s diameter.
Hinge: The hinge is the uncut wood between the notch and the felling cut. It controls the direction and speed of the fall.
Felling Cut (Back Cut): This cut is made on the opposite side of the tree from the notch, slightly above the horizontal cut. Leave enough wood to form the hinge.
Wedges: Use felling wedges to help direct the fall and prevent the saw from getting pinched. Insert the wedges into the felling cut before completing the cut.

Felling Techniques:

Conventional Felling: This is the most common felling technique.
Hinge Felling: This technique is used for trees with a strong lean.
Bore Cut: This technique is used for larger trees to prevent barber chairing (splitting up the trunk).

Safety Considerations:

Wear Appropriate Safety Gear: This includes a helmet, eye protection, hearing protection, gloves, chainsaw chaps, and sturdy boots.
Maintain a Safe Distance: Keep bystanders at least two tree lengths away from the felling area.
Be Aware of Wind Conditions: Avoid felling trees in high winds.
Never Work Alone: Always have someone nearby in case of an emergency.

Measurements and Specs: The hinge should typically be about 80% of the tree diameter for optimal control. The wedges should be made of plastic or aluminum to avoid damaging the chain if you accidentally cut into them.

My Experience: I once felled a tree that had a hidden lean. As I made the felling cut, the tree started to fall in the wrong direction. Fortunately, I had planned my escape route and was able to get out of the way before the tree fell. This experience taught me the importance of carefully assessing the tree and planning for unexpected events.

5. Proper Fueling and Storage: Extending the Life of Your Chainsaw

Proper fueling and storage are essential for maintaining the performance and longevity of your MS 251 C.

Fueling:

Use Fresh Fuel: Gasoline can degrade over time, especially when mixed with oil. Use fresh fuel that is no more than 30 days old.
Mix Fuel and Oil Properly: Use the correct fuel-to-oil ratio (50:1). Use a measuring container to ensure accurate mixing.
Use a Fuel Stabilizer: Add a fuel stabilizer to the fuel to prevent it from degrading during storage.
Fill the Fuel Tank Carefully: Avoid spilling fuel. Wipe up any spills immediately.
Use a Funnel: Use a funnel to prevent fuel from spilling.

Storage:

Drain the Fuel Tank: Before storing the chainsaw for an extended period, drain the fuel tank completely.
Run the Engine Until it Stalls: This will ensure that there is no fuel left in the carburetor.
Remove the Spark Plug: Remove the spark plug and pour a small amount of engine oil into the cylinder. Pull the starter cord a few times to distribute the oil. Replace the spark plug.
Clean the Chainsaw: Remove sawdust and debris from the chainsaw.
Store the Chainsaw in a Dry Place: Store the chainsaw in a dry, well-ventilated place.
Cover the Chainsaw: Cover the chainsaw to protect it from dust and moisture.

Strategic Advantages: Proper storage prevents rust, corrosion, and fuel degradation, which can lead to costly repairs.

My Experience: I once left my MS 251 C stored with fuel in the tank for several months. When I tried to start it, the fuel had turned into a gummy residue that clogged the carburetor. I had to disassemble and clean the carburetor before the saw would run properly. This experience taught me the importance of properly preparing the chainsaw for storage.

Technical Details: Fuel stabilizers typically cost around $10-$15 per bottle and can extend the life of your fuel for up to 12 months.

Next Steps

Now that you have a solid understanding of the Stihl MS 251 C chainsaw basics, it’s time to put your knowledge into practice. Start by practicing the starting procedures. Then, learn how to sharpen your chain properly. Finally, familiarize yourself with safe felling techniques. Remember to always prioritize safety and wear appropriate safety gear.

Here are some concrete actions you can take:

Review the Stihl MS 251 C Owner’s Manual: This is your primary source of information for your specific model.
Watch Online Tutorials: There are many excellent videos available that demonstrate chainsaw techniques.
Attend a Chainsaw Safety Course: This is a great way to learn from experienced professionals and practice safe techniques in a controlled environment.
Practice in a Safe Area: Start by practicing on small pieces of wood in a safe, open area.
Seek Guidance from Experienced Users: Talk to experienced chainsaw users and ask for their advice.

By following these tips and taking the necessary precautions, you can safely and effectively use your Stihl MS 251 C chainsaw for a wide range of wood processing and firewood preparation tasks. Remember, the key is to practice, be patient, and always prioritize safety. Now get out there and make some sawdust!

Stihl MS 251 C Chainsaw Basics (5 Pro Tips)