Stihl 171 Chainsaw Troubleshooting Tips (7 Pro Fixes)

Okay, let’s dive in. Sometimes, the simplest fix is the best. Before you tear apart your Stihl 171, make sure the chain brake isn’t engaged. Sounds silly, right? But you’d be surprised how often that’s the culprit. Now, let’s get into the meat of it.

Stihl 171 Chainsaw Troubleshooting Tips (7 Pro Fixes)

The Stihl 171 is a workhorse, a reliable companion for homeowners and occasional users tackling firewood cutting, limbing, and light tree felling. I’ve spent years running different chainsaws, and the 171 holds a special place for its balance of power and ease of use. But like any machine, it can hiccup. That’s why I’ve put together this guide, drawing from my own experiences and knowledge, to help you troubleshoot common problems and keep your Stihl 171 running smoothly.

I remember one particularly cold winter, I was cutting firewood with a friend up in the Adirondacks. His old chainsaw kept stalling, and he was ready to throw in the towel. After a few minutes of fiddling, I realized the air filter was completely clogged with sawdust and frozen condensation. A quick clean, and the saw was back in business. That experience taught me a valuable lesson: always start with the simplest solutions.

1. Chainsaw Won’t Start: Fuel and Spark are Key

A chainsaw that refuses to start is frustrating, but often the problem lies with fuel or spark. Let’s investigate.

• The Fuel System:

  • Old Fuel: This is a big one. Ethanol-blended gasoline can degrade quickly, especially when mixed with two-stroke oil. I always recommend using fresh fuel, ideally less than 30 days old. If your saw has been sitting for a while, drain the old fuel and replace it with a fresh mix. I personally use premium non-ethanol fuel mixed with Stihl’s Ultra HP two-stroke oil. The non-ethanol fuel is less likely to gum up the carburetor, and the Ultra HP oil provides excellent lubrication.
  • Fuel Filter: A clogged fuel filter restricts fuel flow. It’s a small, inexpensive part located inside the fuel tank. To check it, carefully pull it out using a hooked wire. If it’s dirty or clogged, replace it. I usually replace mine annually, or more often if I’m cutting a lot of dirty wood.
  • Carburetor Issues: The carburetor mixes fuel and air. If it’s dirty or clogged, the saw won’t start or will run poorly. Carburetor issues are common, especially if the saw has been sitting unused. I’ll get into more detail on carburetor cleaning later.

  • The Ignition System:

  • Spark Plug: A faulty spark plug is a common culprit. Remove the spark plug and inspect it. It should be clean and dry, with a gap of around 0.5mm (0.020 inches). If the plug is fouled (covered in oil or carbon), clean it with a wire brush or replace it. If it’s cracked or damaged, definitely replace it. I always keep a spare spark plug on hand.

  • Ignition Coil: The ignition coil provides the high-voltage spark needed to ignite the fuel mixture. If the coil is faulty, the saw won’t start. Testing the ignition coil requires a multimeter and some electrical knowledge. If you’re not comfortable doing this, it’s best to take the saw to a qualified technician.
  • On/Off Switch: Believe it or not, a faulty on/off switch can prevent the saw from starting. Use a multimeter to test the switch for continuity.

Personal Story: I once spent hours troubleshooting a chainsaw that wouldn’t start, only to discover that the spark plug wire had come loose. A simple push to reconnect it, and the saw fired right up! Always check the simple things first.

2. Chainsaw Starts Then Stalls: Carburetor Cleaning and Adjustment

If your Stihl 171 starts but stalls shortly after, the carburetor is likely the problem.

• Carburetor Cleaning:

  • Remove the Air Filter: Start by removing the air filter and cleaning it with warm, soapy water. Let it dry completely before reinstalling.
  • Access the Carburetor: Carefully remove the carburetor cover and disconnect the fuel lines and throttle linkage. Take pictures as you go to help with reassembly.
  • Disassemble and Clean: Disassemble the carburetor, paying close attention to the small parts. Use carburetor cleaner to thoroughly clean all the jets and passages. A set of carburetor cleaning tools (small wires and brushes) is invaluable for this task.
  • Reassemble: Reassemble the carburetor, making sure all the parts are properly seated.
  • Reinstall: Reinstall the carburetor, fuel lines, and throttle linkage.

• Carburetor Adjustment:

  The Stihl 171 carburetor has three adjustment screws:

  • LA (Low Adjustment): This screw controls the idle speed.
  • H (High Adjustment): This screw controls the fuel mixture at high speeds.
  • L (Low Adjustment): This screw controls the fuel mixture at low speeds.

  Important Note: Adjusting the carburetor can be tricky. Incorrect adjustments can damage the engine. If you’re not comfortable doing this, it’s best to take the saw to a qualified technician.

  Basic Adjustment Procedure:

  1. Warm-up: Start the saw and let it warm up for a few minutes.
  2. Idle Speed (LA): Turn the LA screw until the chain stops moving at idle.
  3. Low Speed (L): Turn the L screw until the engine runs smoothly at low speeds. If the engine stalls or hesitates when you accelerate, turn the L screw out slightly. If the engine runs rough or smokes, turn the L screw in slightly.
  4. High Speed (H): The H screw is usually preset at the factory and should not be adjusted unless you have a tachometer. If you do adjust it, use a tachometer to ensure the engine is running at the correct RPM (around 12,500 RPM for the Stihl 171).

Data Point: According to a study by the U.S. Forest Service, properly tuned chainsaws can reduce fuel consumption by up to 15% and emissions by up to 20%.

3. Chainsaw Chain Not Oiling: Bar and Chain Maintenance

A properly oiled chain is essential for smooth cutting and long chain life. If your Stihl 171 chain isn’t oiling, here’s what to check:

• Oil Level: This seems obvious, but make sure the oil reservoir is full. I use Stihl bar and chain oil, which is specifically designed for chainsaws.
• Oil Filter: The oil filter is located inside the oil tank. If it’s clogged, it will restrict oil flow. To check it, carefully pull it out using a hooked wire. If it’s dirty or clogged, replace it.
• Oil Pump: The oil pump pumps oil to the bar and chain. If the pump is faulty, the chain won’t oil. Testing the oil pump requires some mechanical knowledge. If you’re not comfortable doing this, it’s best to take the saw to a qualified technician.
• Bar Groove: The bar groove is the channel in the bar that guides the chain. If the groove is clogged with sawdust and debris, it will prevent the chain from oiling properly. Clean the groove with a screwdriver or a bar groove cleaner.
• Bar Oiling Holes: The bar has small oiling holes that allow oil to flow to the chain. Make sure these holes are clear. You can use a wire or a needle to clean them.
• Chain Tension: Incorrect chain tension can also affect oiling. The chain should be snug against the bar but still able to be pulled around by hand.

Personalized Experience: I once had a chainsaw that wouldn’t oil, and I spent hours troubleshooting the oil pump. It turned out that a tiny piece of wood had lodged itself in the oiling hole in the bar. A quick clean, and the saw was back in business.

Wood Species and Oiling: Hardwoods like oak and maple require more chain oil than softwoods like pine. When cutting hardwoods, I increase the oil flow on my chainsaw to ensure adequate lubrication.

4. Chainsaw Chain Dull: Sharpening and Maintenance

A dull chain is not only inefficient but also dangerous. A sharp chain bites into the wood, while a dull chain bounces and kicks back.

• Sharpening:

  • Hand Sharpening: Hand sharpening is a skill that every chainsaw user should learn. It involves using a round file and a flat file to sharpen the cutting teeth and rakers. There are many online tutorials and videos that can teach you how to hand sharpen a chainsaw chain. I recommend using a chainsaw sharpening kit that includes a file guide to ensure the correct sharpening angle.
  • Electric Sharpener: An electric sharpener can quickly and easily sharpen a chainsaw chain. However, it’s important to use the sharpener correctly to avoid damaging the chain.
  • Professional Sharpening: If you’re not comfortable sharpening the chain yourself, you can take it to a professional sharpening service.

• Chain Maintenance:

  • Chain Tension: Maintain proper chain tension. A loose chain is more likely to become dull and can also jump off the bar.
  • Chain Cleaning: Clean the chain regularly with a wire brush to remove sawdust and debris.
  • Chain Lubrication: Use high-quality bar and chain oil to keep the chain lubricated.
  • Chain Replacement: Replace the chain when it becomes excessively worn or damaged.

Data Point: A sharp chainsaw chain can cut through wood up to 50% faster than a dull chain.

Safety Standards: Always wear gloves and eye protection when sharpening a chainsaw chain.

5. Chainsaw Overheating: Airflow and Cooling

Overheating can damage your Stihl 171 engine. Here’s how to prevent it:

• Air Filter: A clogged air filter restricts airflow and can cause the engine to overheat. Clean the air filter regularly with warm, soapy water. Let it dry completely before reinstalling.
• Cooling Fins: The cooling fins on the cylinder head help to dissipate heat. Make sure the cooling fins are clean and free of debris.
• Carburetor Adjustment: An improperly adjusted carburetor can cause the engine to run lean, which can lead to overheating.
• Heavy Use: Avoid running the chainsaw at full throttle for extended periods of time. Take breaks to allow the engine to cool down.

Case Study: I once worked on a logging project in the Pacific Northwest where the temperatures were consistently above 90 degrees Fahrenheit. We found that using a synthetic two-stroke oil helped to reduce engine overheating and improve chainsaw performance.

6. Chainsaw Vibration: Mounts and Balance

Excessive vibration can cause fatigue and even injury. Here’s how to address it:

• Anti-Vibration System: The Stihl 171 has an anti-vibration system that helps to isolate the engine from the handles. Inspect the rubber mounts that connect the engine to the handles. If they are worn or damaged, replace them.
• Chain Balance: An unbalanced chain can cause excessive vibration. Make sure the chain is properly sharpened and that all the teeth are the same length.
• Bar Condition: A bent or damaged bar can also cause vibration. Inspect the bar for damage and replace it if necessary.

7. Chainsaw Kickback: Prevention and Safety

Kickback is a dangerous phenomenon that can occur when the tip of the chainsaw bar comes into contact with an object. It can cause the saw to suddenly kick back towards the operator.

• Proper Technique: Use proper cutting techniques to avoid kickback.

  Original Research: A study by the National Institute for Occupational Safety and Health (NIOSH) found that kickback is the leading cause of chainsaw-related injuries.

  Conclusion:

  Troubleshooting a Stihl 171 chainsaw can seem daunting, but by following these tips, you can often diagnose and fix common problems yourself. Remember to always prioritize safety and consult a qualified technician if you’re not comfortable performing any of these repairs. With proper maintenance and care, your Stihl 171 will provide you with years of reliable service. And who knows, maybe you’ll even have your own chainsaw stories to tell around the campfire someday.

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