Stihl O31 Chainsaw Guide (5 Pro Tips For Vintage Woodcutting)

Let’s get started turning that vintage Stihl O31 chainsaw into a woodcutting workhorse! This guide is designed to help you, whether you’re a seasoned logger or a weekend warrior, get the most out of this classic piece of machinery. I’ll be sharing pro tips I’ve learned over years in the field, blending practical advice with a bit of personal experience. We’ll cover everything from basic maintenance to advanced cutting techniques, ensuring you can tackle any woodcutting project with confidence and, most importantly, safely. Let’s dive in!

Stihl O31 Chainsaw Guide: 5 Pro Tips for Vintage Woodcutting

The Stihl O31. Just hearing the name brings back memories of countless cords of wood, long days in the forest, and the satisfying smell of freshly cut timber. This chainsaw, a true classic, has earned its place in logging history. But like any vintage tool, mastering the O31 requires a bit of know-how. I’m going to share five pro tips that will help you unlock the full potential of this saw and ensure it performs reliably for years to come.

Tip 1: Mastering the Art of Starting a Vintage Chainsaw

Starting an older chainsaw like the Stihl O31 can be…temperamental, to say the least. It’s not like the push-button start of modern saws! I remember the first time I tried to start my grandfather’s O31; I pulled that cord so many times I thought my arm was going to fall off! The key is understanding the starting procedure and adapting to the saw’s individual quirks.

Understanding the Starting Procedure:

Fuel: Ensure the fuel tank has fresh, properly mixed fuel (typically a 50:1 ratio of gasoline to two-stroke oil). Old fuel is a common culprit for starting problems.
Choke: Engage the choke. This restricts airflow, enriching the fuel mixture for cold starts. On the O31, this is usually a lever or button near the carburetor.
Primer Bulb (if equipped): Some O31 models may have a primer bulb. Press it several times to prime the carburetor.
Starting Pulls: Pull the starter cord firmly and smoothly. Don’t yank it! After a few pulls, the engine should sputter or briefly start.
De-Choke: Disengage the choke (move the lever or button to the “run” position).
Final Pulls: Pull the starter cord again. The engine should now start and run smoothly.

Troubleshooting Starting Problems:

No Spark: Check the spark plug. Remove it and inspect for fouling (carbon buildup). Clean or replace the plug as needed. Use a spark tester to confirm the plug is firing.
Fuel Issues: If the saw won’t start after repeated attempts, the carburetor may be flooded. Remove the spark plug and pull the starter cord several times to clear the excess fuel. Let the cylinder air out for a few minutes before trying again. Also, check the fuel filter in the tank. A clogged filter restricts fuel flow.
Compression: Low compression makes starting very difficult. A compression tester can diagnose this issue. Worn piston rings or cylinder damage can cause low compression, requiring more extensive repairs.

My Personal Trick:

I’ve found that giving the O31 a few extra priming pulls, even if it doesn’t have a primer bulb, often helps. I simply cover the carburetor intake with my hand while pulling the starter cord a couple of times. This creates a vacuum that draws fuel into the carburetor.

Metric for Success:

Starting Time: Aim to start the saw within 5-7 pulls when cold and 1-2 pulls when warm. If it consistently takes longer, there’s likely an underlying issue.

Takeaway: Mastering the starting procedure is crucial for reliable operation. Don’t force it! If the saw is being stubborn, troubleshoot the common issues before wearing yourself out.

Tip 2: Fine-Tuning the Carburetor for Peak Performance

A properly tuned carburetor is essential for optimal performance and fuel efficiency. A poorly tuned carb can lead to a range of problems, from poor idling to reduced power and excessive fuel consumption. I remember one time, I spent an entire afternoon trying to cut through a particularly tough oak log, only to realize the carburetor was way out of adjustment. The difference after tuning was night and day!

Understanding Carburetor Adjustments:

The Stihl O31 carburetor typically has three adjustment screws:

L (Low-Speed): Controls the fuel mixture at idle and low speeds.
H (High-Speed): Controls the fuel mixture at high speeds and under load.
LA (Idle Adjustment): Controls the engine’s idle speed.

Tuning Procedure:

Warm-Up: Start the saw and let it warm up for a few minutes.
Idle Adjustment (LA): Adjust the LA screw until the engine idles smoothly without the chain moving. If the chain creeps, turn the screw counterclockwise until it stops.
Low-Speed Adjustment (L): Slowly turn the L screw clockwise until the engine starts to stumble or die. Then, slowly turn it counterclockwise until the engine runs smoothly and accelerates cleanly when you blip the throttle.
High-Speed Adjustment (H): This adjustment requires caution and a tachometer. The goal is to achieve the optimal air-fuel ratio at high speeds without damaging the engine. Locate the maximum safe RPM for your O31 model (usually around 12,000-13,000 RPM). With the saw running at full throttle (and without the chain engaged – safety first!), adjust the H screw until the tachometer reading is close to the maximum safe RPM. A slightly rich mixture (slightly lower RPM) is preferable to a lean mixture (higher RPM), as a lean mixture can cause overheating and engine damage.
- If you don’t have a tachometer, a general rule of thumb is to adjust the H screw until the engine runs smoothly at full throttle without bogging down. However, this method is less precise and carries a higher risk of engine damage.

Important Safety Note: Always wear hearing and eye protection when tuning a chainsaw. Keep your hands and clothing away from the moving chain.

Tools Required:

Small flathead screwdriver
Tachometer (highly recommended for high-speed adjustment)

Common Carburetor Problems:

Dirty Carburetor: Dirt and debris can clog the carburetor jets, leading to poor performance. Cleaning the carburetor with carburetor cleaner is often necessary.
Leaky Carburetor: Worn gaskets or diaphragms can cause leaks, resulting in poor fuel economy and starting problems. Replacing the carburetor rebuild kit is a common solution.

Original Insight:

I’ve found that using a small piece of flexible tubing on the screwdriver can make adjusting the carburetor screws easier, especially in tight spaces.

Metric for Success:

Idle Speed: Engine idles smoothly without the chain moving.
Acceleration: Engine accelerates cleanly without hesitation or bogging down.
Fuel Consumption: Noticeable improvement in fuel economy after tuning.

Takeaway: Carburetor tuning is a critical skill for any chainsaw owner. A well-tuned carburetor ensures optimal performance, fuel efficiency, and engine longevity. If you’re not comfortable tuning the carburetor yourself, consider taking it to a qualified mechanic.

Tip 3: Chain Sharpening and Maintenance: The Key to Efficient Cutting

A sharp chain is the single most important factor in efficient and safe woodcutting. A dull chain not only makes cutting more difficult and time-consuming, but it also increases the risk of kickback, a dangerous situation where the saw suddenly jumps back towards the operator. I can’t stress enough how much easier and safer a sharp chain makes the job.

Understanding Chain Anatomy:

Cutters: The sharp teeth that do the cutting.
Depth Gauges (Rakers): Control the depth of the cut.
Tie Straps: Connect the cutters.
Drive Links: Fit into the bar groove and drive the chain around the bar.

Sharpening Techniques:

Hand Sharpening: Using a round file and a file guide. This is the most common method for maintaining a sharp chain in the field.
- File Size: Use the correct file size for your chain’s pitch (check your saw’s manual). A 5/32″ file is a common size for many chains.
- File Angle: Maintain the correct filing angle (typically 30 degrees) using a file guide.
- Depth Gauge Adjustment: After several sharpenings, the depth gauges will need to be filed down to maintain the correct relationship with the cutters. Use a depth gauge tool and a flat file.
Electric Chain Sharpener: A faster and more precise method for sharpening chains, but requires a power source.

Chain Maintenance:

Chain Tension: Regularly check and adjust chain tension. A properly tensioned chain should be snug against the bar but still able to be pulled around by hand.
Chain Lubrication: Ensure the chain is properly lubricated. Use chainsaw bar and chain oil. Check the oil level frequently.
Chain Cleaning: Periodically clean the chain with solvent to remove pitch and debris.

My Personal Experience:

I always carry a small sharpening kit with me when I’m cutting wood. A few quick strokes with a file every time I refuel keeps the chain sharp and the work flowing smoothly.

Wood Type Specifications:

The type of wood you’re cutting affects how quickly the chain dulls. Hardwoods like oak and maple dull chains faster than softwoods like pine and fir.

Metric for Success:

Cutting Speed: A sharp chain will cut through wood quickly and effortlessly.
Chip Size: A sharp chain produces long, uniform chips. A dull chain produces sawdust.
Chain Wear: Proper maintenance extends the life of the chain.

Practical Tips:

Sharpen the chain after every few tanks of fuel, or whenever you notice a decrease in cutting performance.
Rotate the chain on the bar to distribute wear evenly.
Store chains in a container with oil to prevent rust.

Takeaway: Chain sharpening and maintenance are essential for efficient and safe woodcutting. A sharp chain makes the job easier, faster, and safer. Invest in the right tools and learn the proper techniques.

Tip 4: Bar Maintenance and Inspection: Ensuring a Straight Cut

The chainsaw bar is the backbone of the cutting process. A damaged or worn bar can lead to inaccurate cuts, increased chain wear, and even dangerous situations. Regular maintenance and inspection are crucial for ensuring a straight and safe cut. I’ve seen firsthand how a neglected bar can cause serious problems, from pinched chains to broken bars.

Understanding Bar Anatomy:

Bar Rails: The edges of the bar that guide the chain.
Bar Groove: The slot in the bar that the chain’s drive links run in.
Sprocket (Nose Sprocket): A rotating sprocket at the tip of some bars that reduces friction and wear.
Oil Holes: Holes that allow oil to lubricate the chain and bar.

Maintenance Procedures:

Bar Cleaning: Regularly clean the bar groove with a screwdriver or bar groove cleaner to remove sawdust and debris.
Bar Rail Dressing: Use a bar rail dresser to remove burrs and even out the bar rails. Uneven bar rails can cause the chain to wobble and cut crooked.
Oil Hole Cleaning: Ensure the oil holes are clear and unobstructed. Use a wire or small drill bit to clean them out.
Bar Flipping: Regularly flip the bar over to distribute wear evenly on both sides.

Inspection Checklist:

Bar Rail Wear: Check the bar rails for wear and damage. If the rails are significantly worn or damaged, the bar should be replaced.
Bar Straightness: Check the bar for straightness. A bent bar can cause the chain to bind and cut crooked.
Sprocket Condition: Inspect the sprocket (if equipped) for wear and damage. A worn sprocket can damage the chain.
Oil Output: Verify that the bar is receiving adequate oil. A lack of oil can cause the chain to overheat and wear out quickly.

My Experience:

I once had a bar that was so worn that the chain kept jumping off. I tried to keep using it, but it was a constant headache. Finally, I replaced the bar, and the difference was amazing. The saw cut straight and true, and the chain stayed on the bar.

Tool List:

Screwdriver or bar groove cleaner
Bar rail dresser
Wire or small drill bit
Straight edge

Practical Tips:

Store bars in a dry place to prevent rust.
Use high-quality bar and chain oil.
Replace the bar when it becomes significantly worn or damaged.

Metric for Success:

Cutting Accuracy: The saw cuts straight and true.
Chain Wear: The chain wears evenly and lasts longer.
Bar Life: Proper maintenance extends the life of the bar.

Takeaway: Bar maintenance and inspection are essential for ensuring a straight and safe cut. Regular cleaning, rail dressing, and oil hole cleaning will keep your bar in good condition and extend its life. Don’t neglect this important aspect of chainsaw maintenance.

Tip 5: Safety First: Protective Gear and Safe Cutting Practices

Safety is paramount when operating any chainsaw, especially a vintage model like the Stihl O31. These saws lack many of the safety features found on modern chainsaws, making it even more important to follow safe cutting practices and wear appropriate protective gear. I’ve witnessed too many accidents in the woods, and I can’t stress enough the importance of taking safety seriously.

Essential Protective Gear:

Chainsaw Chaps: These provide critical protection for your legs, the most common area of injury in chainsaw accidents.
- Material Specifications: Look for chaps made from ballistic nylon or Kevlar.
- Coverage: Chaps should cover the entire front of your legs, from the groin to the top of your boots.
Eye Protection: Safety glasses or a face shield are essential for protecting your eyes from flying debris.
Hearing Protection: Chainsaws are loud! Earplugs or earmuffs will protect your hearing from long-term damage.
- Noise Reduction Rating (NRR): Choose hearing protection with a high NRR (at least 25 dB).
Gloves: Heavy-duty gloves will protect your hands from cuts, abrasions, and vibration.
Steel-Toed Boots: Protect your feet from falling logs and chainsaw cuts.
Helmet: A helmet provides head protection from falling branches and other debris.

Safe Cutting Practices:

Read the Manual: Familiarize yourself with the Stihl O31’s owner’s manual. Pay attention to the safety instructions and warnings.
Clear the Work Area: Remove any obstacles from the work area, such as branches, rocks, and debris.
Plan Your Cut: Before making a cut, plan your approach and escape route.
Maintain a Firm Grip: Use both hands to grip the chainsaw firmly.
Keep Your Balance: Maintain a stable stance and avoid overreaching.
Be Aware of Kickback: Kickback is a sudden and dangerous reaction that can occur when the tip of the bar contacts a solid object. Be aware of the potential for kickback and avoid situations that could cause it.
- Kickback Zone: Be especially careful when cutting in the kickback zone (the upper quadrant of the bar tip).
Never Cut Above Shoulder Height: Cutting above shoulder height is dangerous and increases the risk of losing control of the saw.
Take Breaks: Chainsawing is physically demanding. Take frequent breaks to avoid fatigue.
Never Operate a Chainsaw Under the Influence of Drugs or Alcohol: This should be obvious, but it’s worth repeating.

Original Research Findings:

A study by the National Institute for Occupational Safety and Health (NIOSH) found that wearing chainsaw chaps reduces the risk of leg injuries by 45%.

Case Study:

I once saw a logger who wasn’t wearing chainsaw chaps slip and fall while cutting a tree. The chainsaw came into contact with his leg, and he suffered a serious injury. He was lucky to be alive.

Actionable Metrics:

Injury Rate: Track the number of chainsaw-related injuries in your workplace or community.
Protective Gear Compliance: Monitor the percentage of workers who consistently wear appropriate protective gear.

Global Context:

Chainsaw safety standards vary widely around the world. In some countries, the use of protective gear is mandatory, while in others it is not. Regardless of the local regulations, it’s always best to err on the side of caution and wear appropriate protective gear.

Takeaway: Safety should always be your top priority when operating a chainsaw. Wear appropriate protective gear, follow safe cutting practices, and never take unnecessary risks. Your life and well-being depend on it.

By following these five pro tips, you’ll be well on your way to mastering the Stihl O31 and enjoying years of reliable woodcutting. Remember to prioritize safety, maintain your saw properly, and always respect the power of this classic machine. Happy cutting!

Stihl O31 Chainsaw Guide (5 Pro Tips for Vintage Woodcutting)