How to Start a Stihl MS170 (Troubleshooting Tips for Arborists)

The echo of axes ringing through the forests of antiquity has always been intertwined with the warmth of a hearth fire. Even before the advent of the chainsaw, the preparation of wood for shelter, heat, and cooking was a fundamental human endeavor. From the Roman legionary felling trees for fortifications to the medieval peasant gathering firewood for the winter, the ability to efficiently process wood has been a cornerstone of survival and progress. Today, while the tools have evolved, the essential challenge remains: how to do it efficiently and cost-effectively.

How to Start a Stihl MS170 (Troubleshooting Tips for Arborists)

The Stihl MS170 is a workhorse. It’s the kind of chainsaw that many arborists, homeowners, and even seasoned loggers keep around for smaller jobs. It’s lightweight, relatively inexpensive, and reliable… when it starts. But like any machine, it can be finicky. And when that familiar roar turns into a frustrated sputter, knowing how to troubleshoot can save you time, money, and a whole lot of frustration.

Why a Reliable Start Matters (And the Costs of Failure)

Before we dive into the nitty-gritty, let’s talk about why getting your MS170 started reliably is so important.

• Lost Productivity: Time is money. For an arborist, a stalled chainsaw means delayed job completion, potentially impacting client satisfaction and future referrals. Even for a homeowner, a non-starting saw can turn a simple weekend project into a day-long headache. I’ve seen crews lose hours on a job site because of a stubborn saw – hours that could have been spent felling, limbing, and getting the job done.
• Increased Labor Costs: If you’re paying a crew by the hour, diagnosing and fixing a chainsaw problem can quickly add up. The cost of downtime can easily eclipse the price of a new saw if the problem is persistent and unresolved.
• Potential for Damage: Repeatedly yanking on the starter cord in frustration can damage the recoil mechanism. Replacing that can cost you parts and labor. Plus, attempting to force a start when there’s a deeper issue can lead to more significant problems down the line.
• Impact on Firewood Preparation Costs: For those of us who rely on chainsaws for firewood, a delayed start can throw off our entire schedule. It can mean scrambling to get wood cut before winter sets in, potentially forcing us to buy more expensive, pre-cut firewood.

So, knowing how to troubleshoot your MS170 is not just about convenience, it’s about protecting your investment, minimizing costs, and maximizing efficiency.

Understanding the Stihl MS170: A Quick Overview

The MS170 is a two-stroke engine. This means it requires a mixture of gasoline and oil to lubricate the engine. It also means it has a relatively simple design, making it easier to troubleshoot than more complex four-stroke engines.

Here are the key components we’ll be focusing on:

• Fuel Tank: Holds the gasoline/oil mixture.
• Fuel Line: Carries fuel from the tank to the carburetor.
• Fuel Filter: Prevents debris from entering the carburetor.
• Carburetor: Mixes fuel and air for combustion.
• Spark Plug: Ignites the fuel/air mixture.
• Ignition Coil: Provides the electrical spark to the spark plug.
• Air Filter: Prevents debris from entering the engine.
• Starter: Engages the engine to start the combustion process.
• Muffler: Reduces engine noise and directs exhaust gases.

Troubleshooting Steps: A Systematic Approach

When your MS170 refuses to start, resist the urge to immediately tear everything apart. Instead, follow a systematic approach to identify the problem. I’ve learned over the years that methodical troubleshooting saves time and prevents unnecessary repairs.

1. Fuel Issues: The Most Common Culprit

Fuel problems are the number one reason why chainsaws fail to start.

• Check the Fuel Tank: Obvious, but essential. Is there fuel in the tank? Don’t assume – actually look. I’ve kicked myself more than once for overlooking this simple step.
• Fuel Quality: Old fuel is a major culprit. Gasoline degrades over time, especially when mixed with oil. If the fuel has been sitting in the saw for more than a month, drain it and replace it with fresh fuel. I always recommend using fuel stabilizer, especially if the saw will be stored for extended periods. This can prevent fuel degradation and carburetor gumming.
  • Cost of Fuel Stabilizer: A bottle of fuel stabilizer typically costs around \$10-\$20 and can treat several gallons of fuel. This is a small price to pay compared to the cost of carburetor repair or replacement.
  • Data Point: Studies show that gasoline can start to degrade in as little as 30 days, leading to reduced engine performance and starting problems.
• Fuel Mixture: Are you using the correct fuel-to-oil ratio? The MS170 typically requires a 50:1 mixture (50 parts gasoline to 1 part oil). Using the wrong ratio can lead to engine damage or starting problems. I always use a pre-measured oil packet to ensure the correct mixture.
  • Cost of Two-Stroke Oil: A high-quality two-stroke oil packet costs around \$1-\$3 per packet.
  • Data Point: Using the wrong fuel-to-oil ratio is a leading cause of engine damage in two-stroke engines.
• Fuel Filter: A clogged fuel filter restricts fuel flow to the carburetor. Remove the fuel filter from the tank (usually accessed through the fuel filler opening) and inspect it. If it’s dirty or clogged, replace it. Fuel filters are inexpensive and easy to replace.
  • Cost of Fuel Filter: A replacement fuel filter for the MS170 typically costs around \$5-\$10.
  • Personal Experience: I once spent hours trying to diagnose a starting problem, only to discover a completely clogged fuel filter. It’s now one of the first things I check.
• Fuel Line: Inspect the fuel line for cracks, kinks, or leaks. A damaged fuel line can prevent fuel from reaching the carburetor. Replace the fuel line if necessary.
  • Cost of Fuel Line: A replacement fuel line for the MS170 typically costs around \$5-\$15.
• Priming Bulb: The priming bulb is used to draw fuel into the carburetor. Press the priming bulb several times until you see fuel flowing through it. If the bulb is cracked or damaged, replace it.
  • Cost of Priming Bulb: A replacement priming bulb for the MS170 typically costs around \$3-\$8.

2. Spark Issues: No Spark, No Start

If fuel isn’t the problem, the next thing to check is the spark.

• Spark Plug: Remove the spark plug and inspect it. Look for cracks, carbon buildup, or excessive wear. Clean the spark plug with a wire brush or replace it if necessary. I always carry a spare spark plug in my toolkit.
  • Cost of Spark Plug: A replacement spark plug for the MS170 typically costs around \$3-\$10.
  • Personal Experience: I’ve had spark plugs fail unexpectedly in the middle of a job. A quick replacement can get you back up and running in minutes.
• Spark Test: With the spark plug removed, reattach the spark plug wire and ground the spark plug against the engine block. Pull the starter cord. You should see a bright blue spark. If you don’t see a spark, the ignition coil may be faulty.
  • Safety Note: Be careful not to touch the spark plug while pulling the starter cord. You can get a nasty shock.
• Ignition Coil: The ignition coil provides the high-voltage spark to the spark plug. If the spark test fails, the ignition coil may need to be replaced. This is a more complex repair that may require professional assistance.
  • Cost of Ignition Coil: A replacement ignition coil for the MS170 typically costs around \$20-\$50.
  • Note: Replacing the ignition coil requires disconnecting and reconnecting electrical wires. If you’re not comfortable with this, it’s best to take the saw to a qualified repair technician.

3. Air Issues: Restriction Can Cause Problems

The engine needs air to breathe. A clogged air filter can restrict airflow and prevent the saw from starting.

• Air Filter: Remove the air filter and inspect it. If it’s dirty, clean it with soap and water or replace it. I prefer to use compressed air to clean air filters, but be careful not to damage the filter element.
  • Cost of Air Filter: A replacement air filter for the MS170 typically costs around \$5-\$15.
  • Data Point: A clogged air filter can reduce engine power by up to 20%.
• Air Intake: Make sure the air intake is clear of debris. Leaves, sawdust, and other debris can block the air intake and prevent the engine from starting.

4. Carburetor Issues: The Heart of the Engine

The carburetor mixes fuel and air for combustion. A dirty or malfunctioning carburetor can cause starting problems.

• Carburetor Cleaning: Sometimes, a simple cleaning can fix a carburetor problem. Use carburetor cleaner to clean the carburetor jets and passages. You can find carburetor cleaner at most auto parts stores.
  • Cost of Carburetor Cleaner: A can of carburetor cleaner typically costs around \$5-\$10.
• Carburetor Adjustment: The carburetor has adjustment screws that control the fuel-to-air mixture. If the carburetor is not properly adjusted, the engine may not start. Consult the Stihl MS170 owner’s manual for instructions on how to adjust the carburetor. Note: Carburetor adjustment is best left to experienced users or qualified technicians.
• Carburetor Rebuild: If cleaning and adjustment don’t work, the carburetor may need to be rebuilt. This involves disassembling the carburetor, cleaning all the parts, and replacing any worn or damaged components. Carburetor rebuild kits are available for the MS170.
  • Cost of Carburetor Rebuild Kit: A carburetor rebuild kit for the MS170 typically costs around \$15-\$30.
  • Note: Rebuilding a carburetor can be a complex process. If you’re not comfortable with this, it’s best to take the saw to a qualified repair technician.
• Carburetor Replacement: In some cases, it may be more cost-effective to replace the entire carburetor rather than rebuild it. Replacement carburetors are available for the MS170.
  • Cost of Carburetor Replacement: A replacement carburetor for the MS170 typically costs around \$20-\$60.

5. Compression Issues: A Sign of Serious Problems

If you’ve checked fuel, spark, and air, and the saw still won’t start, there may be a compression problem. Compression is the measure of how tightly the engine seals. Low compression can prevent the engine from starting.

• Compression Test: A compression test measures the amount of pressure inside the cylinder. A low compression reading indicates a problem with the piston rings, cylinder, or valves. This is a more complex repair that may require professional assistance.
  • Note: Performing a compression test requires specialized equipment.
• Causes of Low Compression: Low compression can be caused by worn piston rings, a damaged cylinder, or leaking valves. These problems typically require a major engine overhaul.
• Cost of Engine Overhaul: An engine overhaul can be expensive, potentially costing more than the price of a new chainsaw. In some cases, it may be more cost-effective to replace the entire saw.

Cost Breakdown: Repair vs. Replacement

Let’s take a look at the costs associated with repairing the MS170 versus replacing it. This will help you make an informed decision about whether to repair or replace your saw.

• Note: Labor costs are estimates and can vary depending on your location and the repair shop.

Decision Point:

• If the repair costs are approaching or exceeding the cost of a new MS170, it may be more cost-effective to replace the saw.
• Consider the age and condition of the saw. If it’s old and has other problems, it may be better to invest in a new saw.
• If you’re comfortable performing the repairs yourself, you can save on labor costs.

Preventing Future Starting Problems: Proactive Maintenance

The best way to avoid starting problems is to perform regular maintenance on your MS170.

• Use Fresh Fuel: Always use fresh fuel and fuel stabilizer.
• Clean Air Filter Regularly: Clean the air filter after each use.
• Check Spark Plug Regularly: Check the spark plug every few months and replace it if necessary.
• Sharpen the Chain Regularly: A dull chain puts extra strain on the engine.
• Store the Saw Properly: Store the saw in a dry place with the fuel tank empty.
• Regular Servicing: Consider having your saw serviced by a qualified technician at least once a year.

The Arborist’s Perspective: Chainsaw Costs and Budgeting

As an arborist, chainsaw costs are a significant part of my operating budget. Here’s how I manage those costs:

• Chainsaw Selection: I choose chainsaws based on the specific tasks I need to perform. I have different saws for felling, limbing, and pruning.
• Preventative Maintenance: I prioritize preventative maintenance to minimize downtime and extend the life of my saws.
• Crew Training: I train my crew to properly maintain and operate chainsaws.
• Fuel Management: I buy fuel in bulk to save money and use fuel stabilizer to prevent fuel degradation.
• Record Keeping: I keep detailed records of chainsaw repairs and maintenance costs.
• Depreciation: I factor in chainsaw depreciation when calculating my business expenses.
• Regular Replacement: I replace chainsaws on a regular schedule to avoid costly repairs and downtime.

Data Point: A professional arborist can spend \$500-\$2000+ per year on chainsaw maintenance and replacement.

A Case Study: Firewood Preparation Cost Analysis

Let’s look at a case study of firewood preparation to illustrate the impact of chainsaw maintenance on overall costs.

Scenario: You need to prepare 5 cords of firewood for the winter.

Cost Factors:

• Wood Source: \$50-\$150 per cord (depending on the type of wood and source)
• Chainsaw: Stihl MS170
• Chainsaw Fuel: \$5 per gallon
• Chainsaw Oil: \$10 per quart
• Labor: \$20 per hour (if hiring someone to help)
• Equipment Rental: Log splitter rental (\$50 per day)

Cost Breakdown:

Assumptions:

• You are using your own chainsaw.
• Chainsaw maintenance costs are estimated based on regular maintenance.
• You are renting a log splitter for one day.

Impact of Chainsaw Failure:

If your chainsaw fails during the firewood preparation process, it can significantly increase your costs.

• Downtime: Lost time can lead to increased labor costs.
• Repair Costs: Unexpected repairs can add to your expenses.
• Delayed Completion: A delayed completion can mean buying more expensive, pre-cut firewood.

Data Point: A chainsaw failure can add 10-20% to your overall firewood preparation costs.

Practical Tips for Cost Optimization

Here are some practical tips for optimizing your costs when using a chainsaw for wood processing or firewood preparation:

• Buy Wood in Bulk: Buying wood in bulk can save you money on the wood source.
• Season Wood Properly: Properly seasoned wood is easier to cut and split, reducing strain on the chainsaw.
• Use the Right Chainsaw for the Job: Using the right chainsaw for the job can improve efficiency and reduce wear and tear on the saw.
• Sharpen Chains Regularly: A sharp chain makes cutting easier and faster.
• Maintain Your Chainsaw Regularly: Regular maintenance can prevent costly repairs and extend the life of your chainsaw.
• Shop Around for Equipment Rentals: Compare prices from different rental companies to get the best deal on equipment rentals.
• Consider Sharing Equipment: Consider sharing equipment with neighbors or friends to reduce costs.
• Plan Ahead: Planning ahead can help you avoid unexpected costs and delays.
• Learn Basic Chainsaw Repair: Learning basic chainsaw repair can save you money on labor costs.
• Monitor Fuel Consumption: Monitoring fuel consumption can help you identify potential problems with your chainsaw.

Calculations and Formulas

Here are some relevant calculations and formulas that can be helpful in wood processing and firewood preparation:

• Calculating Volume of Logs:
  • Board Feet: (Length in feet x Width in inches x Thickness in inches) / 12
  • Cords: A cord is a stack of wood that measures 4 feet high, 4 feet wide, and 8 feet long. To calculate the volume of a stack of wood in cords, divide the volume in cubic feet by 128.
• Estimating Drying Time:
  • Drying time depends on several factors, including wood species, initial moisture content, and climate. A general rule of thumb is that firewood takes 6-12 months to dry properly.
• Fuel Consumption:
  • Fuel consumption can vary depending on the chainsaw model and the type of work being performed. A general estimate is that a chainsaw consumes 0.5-1 gallon of fuel per hour.

Actionable Takeaways

• Troubleshoot Systematically: Follow a systematic approach to diagnose starting problems.
• Prioritize Preventative Maintenance: Regular maintenance can prevent costly repairs and extend the life of your chainsaw.
• Consider Repair vs. Replacement: Evaluate the costs of repair versus replacement before making a decision.
• Optimize Costs: Implement practical tips to optimize your costs when using a chainsaw.
• Keep Records: Keep detailed records of chainsaw repairs and maintenance costs.
• Invest in Quality Equipment: Investing in quality equipment can save you money in the long run.
• Get Training: Get proper training on chainsaw operation and maintenance.
• Stay Safe: Always prioritize safety when using a chainsaw.

Final Thoughts

The Stihl MS170 is a valuable tool for arborists, homeowners, and anyone who needs to process wood. By understanding the common causes of starting problems and following a systematic approach to troubleshooting, you can keep your saw running smoothly and efficiently. Remember, proactive maintenance is the key to minimizing costs and maximizing the lifespan of your chainsaw. And when the time comes to decide between repair and replacement, carefully consider the costs and benefits of each option. With a little knowledge and effort, you can keep your chainsaw – and your wood processing projects – running like a well-oiled machine. As they say in the logging world, “Keep your chain sharp and your wits sharper!”

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