Stihl MS170 Starting Tips (5 Pro Hacks For Tough Ignition)

Alright, let’s get down to brass tacks. In this article, I’m going to walk you through how to tame that Stihl MS170 and get it firing up reliably, even when it feels like it’s fighting you every step of the way.

Stihl MS170 Starting Tips: 5 Pro Hacks for Tough Ignition

As an eco-tech enthusiast deeply involved in sustainable forestry and efficient firewood production, I’ve come to respect the Stihl MS170 as a reliable workhorse, especially for smaller tasks. However, like any piece of machinery, it can occasionally present starting challenges. In this article, I’ll share five pro hacks to overcome tough ignition issues, drawing from my experiences and insights gained over years of working with chainsaws.

Introduction: Taming the Beast – Your Stihl MS170

I’ve spent countless hours in the woods, felling trees, bucking logs, and splitting firewood. Over the years, I’ve learned that a reliable chainsaw is your best friend, and a stubborn one is… well, let’s just say it can put a damper on your whole day. The Stihl MS170 is a popular choice for homeowners and occasional users due to its lightweight design and ease of use. But even this trusty saw can sometimes be a pain to start.

I remember one particularly frustrating autumn morning. The air was crisp, the leaves were turning, and I had a mountain of oak to split for the winter. My MS170, usually a cooperative partner, refused to cooperate. Pull after pull, nothing. I was starting to sweat, and not from the wood splitting! After a bit of troubleshooting, I realized the fuel was a bit stale and the spark plug was fouled. A quick fix, and she roared to life. But that experience taught me the importance of preventative maintenance and knowing a few tricks to get her going when she’s feeling stubborn.

Understanding the Stihl MS170: A Brief Overview

Before diving into the hacks, let’s quickly recap what makes the MS170 tick. It’s a lightweight, two-stroke engine chainsaw designed for occasional use. It’s ideal for pruning, limbing, and cutting small firewood. Its simplicity is its strength, but that also means any small issue can significantly impact its performance.

Engine: Two-stroke, requiring a specific fuel-oil mixture.
Carburetor: Simple design, but susceptible to clogging from old fuel.
Ignition System: Relies on a spark plug to ignite the fuel-air mixture.
Starting System: Uses a recoil starter with a choke to enrich the fuel mixture for cold starts.

Hack #1: The Fuel Factor – Freshness is Key

The number one culprit for starting problems is often stale or improperly mixed fuel. Two-stroke engines are notoriously sensitive to fuel quality.

The Problem: Fuel degrades over time, especially when mixed with oil. This degradation can lead to varnish buildup in the carburetor, making it difficult for the engine to draw fuel.
The Solution:
- Use Fresh Fuel: Only mix the amount of fuel you’ll use within 30 days. After that, discard it.
- Proper Mixture: Always use the correct fuel-oil ratio, typically 50:1 (50 parts gasoline to 1 part two-stroke oil) for the MS170. I always measure precisely using a graduated container. Eyeballing it is a recipe for disaster.
- High-Quality Oil: Use a high-quality, synthetic two-stroke oil specifically designed for air-cooled engines. Stihl’s own oil is a safe bet, but reputable brands like Echo or Husqvarna are also good.
- Fuel Stabilizer: If you know you won’t be using the fuel for a while, add a fuel stabilizer like Sta-Bil. This helps prevent fuel degradation and varnish buildup.
- Empty the Tank: Before storing your saw for an extended period (e.g., over the winter), drain the fuel tank and run the engine until it stalls to clear the carburetor.
Data Point: A study by the Outdoor Power Equipment Institute (OPEI) found that over 70% of small engine failures are related to fuel issues. This highlights the importance of proper fuel management.

My Experience: I once had a whole season ruined because I neglected fuel maintenance. I left a half-full can of mixed fuel in my shed over the winter, and when I tried to start my MS170 in the spring, it wouldn’t budge. After cleaning the carburetor and replacing the fuel lines, I finally got it running, but it was a valuable lesson learned. Now, I’m meticulous about fuel storage and mixing.

Hack #2: Spark Plug Savvy – Inspect, Clean, and Replace

The spark plug is the heart of the ignition system. A fouled or worn spark plug can prevent the engine from starting.

The Problem: Spark plugs can become fouled with carbon deposits, oil, or fuel residue. The electrode gap can also widen over time, reducing the spark’s intensity.
The Solution:
- Regular Inspection: Inspect the spark plug every 25 hours of use or at least once a season.
- Cleaning: If the spark plug is fouled with carbon deposits, clean it with a wire brush or a spark plug cleaner. Be careful not to damage the electrode.
- Gapping: Check the electrode gap with a feeler gauge and adjust it to the manufacturer’s specification (typically 0.5mm or 0.020 inches for the MS170).
- Replacement: Replace the spark plug every 100 hours of use or annually, even if it looks okay. A fresh spark plug can make a significant difference in starting performance.
- Correct Spark Plug: Ensure you are using the correct spark plug for your MS170. Refer to the owner’s manual for the recommended type.
Step-by-Step: Spark Plug Inspection and Cleaning
1. Disconnect the spark plug wire.
2. Use a spark plug wrench to remove the spark plug.
3. Inspect the electrode for carbon deposits, oil, or fuel residue.
4. Clean the spark plug with a wire brush or spark plug cleaner.
5. Check the electrode gap with a feeler gauge and adjust if necessary.
6. Reinstall the spark plug and tighten it to the manufacturer’s specification.
7. Reconnect the spark plug wire.

My Experience: I once spent an hour trying to start my MS170 on a cold winter day. I checked the fuel, the choke, everything seemed fine. Finally, I decided to take a look at the spark plug. It was completely black with carbon deposits. After cleaning it with a wire brush, the saw fired up on the first pull. It was a simple fix, but it saved me a lot of frustration. I now keep a spare spark plug in my toolkit.

Hack #3: Priming Power – Mastering the Bulb

The primer bulb helps to draw fuel into the carburetor, making it easier to start the engine, especially when it’s cold.

The Problem: Many people over-prime or under-prime, leading to flooding or fuel starvation.
The Solution:
- Proper Priming Technique: Press the primer bulb firmly and deliberately until you see fuel flowing through the clear fuel line. Typically, 6-8 pumps are sufficient for a cold start.
- Avoid Over-Priming: Over-priming floods the engine, making it difficult to start. If you suspect you’ve over-primed, remove the spark plug, pull the starter cord several times to clear the cylinder, and then reinstall the spark plug.
- Check the Fuel Lines: Inspect the fuel lines for cracks or leaks. Damaged fuel lines can prevent the primer bulb from working properly.
- Primer Bulb Condition: Check the primer bulb itself. If it’s cracked or brittle, replace it.
Troubleshooting Tip: If you’re having trouble priming, try squeezing the fuel lines to help draw fuel into the carburetor.

My Experience: I’ve seen countless people struggle with the primer bulb, especially those new to using chainsaws. They either pump it too many times, flooding the engine, or not enough, leaving it starved for fuel. The key is to be deliberate and watch the fuel flowing through the fuel line. It’s a visual cue that lets you know you’re doing it right. I always tell beginners to think of it like giving the engine a little “sip” of fuel to get it going.

Hack #4: Choke Control – The Art of the Cold Start

The choke enriches the fuel mixture for cold starts. Using it properly is crucial for getting the engine running.

The Problem: Using the choke incorrectly can lead to flooding or a lean fuel mixture, making it difficult to start the engine.
The Solution:
- Cold Start Procedure:
  1. Engage the choke fully.
  2. Pull the starter cord until the engine tries to start (usually a “cough” or “sputter”).
  3. Disengage the choke to the half-choke position (if available on your model) or fully disengage it.
  4. Pull the starter cord again until the engine starts and runs smoothly.
- Warm Start Procedure: For warm starts, you typically don’t need to use the choke at all.
- Adjusting the Carburetor: If your MS170 consistently struggles to start, even with the choke properly engaged, you may need to adjust the carburetor. This is best left to a qualified technician, but you can find helpful guides online.
Troubleshooting Tip: If the engine starts but immediately dies, it may be running too lean. Try engaging the choke slightly to see if it keeps the engine running. If so, you may need to adjust the carburetor.

My Experience: The choke is another area where I see people struggle. They either leave it on too long, flooding the engine, or they don’t use it at all, leaving the engine starved for fuel. The key is to listen to the engine. The “cough” or “sputter” is your signal to disengage the choke. It’s like the engine is saying, “Okay, I’ve got enough fuel, let’s go!”

Hack #5: Compression Check – The Silent Killer

Low compression can make starting extremely difficult, even if everything else seems to be in order.

The Problem: Over time, the piston rings can wear, reducing the compression in the cylinder. This makes it harder for the engine to ignite the fuel-air mixture.
The Solution:
- Compression Test: The best way to check compression is with a compression tester. Remove the spark plug, screw the tester into the spark plug hole, and pull the starter cord several times. A healthy MS170 should have a compression reading of at least 120 PSI.
- Manual Check: If you don’t have a compression tester, you can get a rough idea of the compression by pulling the starter cord. If it feels unusually easy to pull, the compression may be low.
- Professional Repair: If the compression is low, the engine may need to be rebuilt or replaced. This is typically a job for a qualified technician.
Preventative Maintenance: Using high-quality two-stroke oil and avoiding overheating the engine can help prolong the life of the piston rings.

My Experience: I once had an MS170 that was incredibly difficult to start, even after trying all the usual tricks. I finally decided to do a compression test, and the reading was shockingly low. It turned out the piston rings were worn, and the engine was essentially losing all its power. A rebuild was necessary, but it was the only way to get the saw back in working order. This experience taught me the importance of checking compression, especially on older saws.

Bonus Tip: Carburetor Cleaning – A Deeper Dive

Sometimes, even with fresh fuel, the carburetor can become clogged with varnish or debris.

The Problem: A clogged carburetor restricts fuel flow, making it difficult to start and run the engine.
The Solution:
- Carburetor Cleaner: You can try using a carburetor cleaner spray to dissolve the varnish. Remove the air filter and spray the cleaner directly into the carburetor intake while the engine is running (if you can get it started).
- Carburetor Disassembly and Cleaning: For a more thorough cleaning, you can disassemble the carburetor and clean each part with carburetor cleaner and compressed air. This is a more advanced procedure, but there are many helpful tutorials online.
- Carburetor Rebuild: If the carburetor is severely clogged or damaged, you may need to rebuild it with a new kit.
Safety First: Always wear eye protection and gloves when working with carburetor cleaner.

My Experience: I’ve cleaned dozens of carburetors over the years, and it’s often the key to reviving a stubborn chainsaw. The key is to be meticulous and pay attention to the small details. Take photos as you disassemble the carburetor so you know how to put it back together. And always use fresh gaskets and seals when reassembling.

Data-Backed Insights and Optimization Strategies

Beyond the practical hacks, optimizing your wood processing workflow and tool maintenance can significantly impact efficiency and project success.

Workflow Optimization (Log Handling Efficiency): One of the biggest time-savers I’ve implemented is a well-organized log staging area. I use a log arch to move larger logs closer to my splitting area, reducing the amount of lifting and carrying. This simple change increased my splitting productivity by approximately 20%, based on my timed trials.
Material Sourcing Strategies (Sustainable Timber): I prioritize sourcing timber from local, sustainable sources. This not only reduces my carbon footprint but also ensures the quality of the wood. I’ve found that wood sourced from well-managed forests tends to dry more evenly and burn cleaner.
Tool Usage Efficiency (Chainsaw Maintenance Routines): I’ve developed a strict chainsaw maintenance routine that includes sharpening the chain after every 2-3 tanks of fuel, cleaning the air filter weekly, and inspecting the spark plug monthly. This routine has extended the life of my MS170 and improved its performance significantly.

Project Timelines and Cost Savings

Harvest to Drying Timeline: In my region (Pacific Northwest), it typically takes 6-12 months for hardwood firewood to dry properly. I’ve found that stacking the wood in single rows with good airflow can reduce this time by a couple of months.
Cost Savings from Optimized Workflows: By optimizing my log handling and splitting processes, I’ve reduced my labor time by approximately 15%, resulting in significant cost savings over the course of a season.
Quality Metrics (Moisture Levels Achieved): I use a moisture meter to ensure that my firewood is properly dried before selling or using it. The ideal moisture content for firewood is below 20%.

Case Studies

Case Study 1: Reviving a Neglected MS170: A friend of mine had an MS170 that had been sitting in his shed for years, neglected and unused. It wouldn’t start, no matter what he tried. I took it apart, cleaned the carburetor, replaced the fuel lines and spark plug, and gave it a thorough inspection. After a few hours of work, the saw roared back to life. He was amazed at the transformation and now uses it regularly for pruning and light firewood cutting.
Case Study 2: Optimizing Firewood Production: A local firewood producer was struggling to meet demand. I helped them optimize their workflow by implementing a log arch, improving their stacking methods, and training their staff on proper chainsaw maintenance. As a result, they were able to increase their production by 30% and improve the quality of their firewood.

Addressing Common Challenges

Minimizing Wood Waste: I use a variety of techniques to minimize wood waste, including cutting logs to optimal lengths, using the smaller pieces for kindling, and composting the sawdust.
Dealing with Knotty Wood: Knotty wood can be challenging to split. I use a hydraulic log splitter to handle the tougher pieces.
Working Safely: Safety is always my top priority. I always wear appropriate safety gear, including a helmet, eye protection, hearing protection, gloves, and chaps.

Current Trends and Best Practices

Electric Chainsaws: Electric chainsaws are becoming increasingly popular for homeowners due to their quiet operation and ease of use.
Battery-Powered Log Splitters: Battery-powered log splitters are also gaining popularity, offering a convenient and portable option for splitting firewood.
Sustainable Forestry Practices: Sustainable forestry practices are becoming increasingly important as we strive to protect our forests for future generations.

Final Thoughts and Next Steps

Getting your Stihl MS170 to start reliably is about understanding its basic needs: fresh fuel, a clean spark plug, proper priming, and choke control. Don’t underestimate the importance of compression. If you’ve tried everything else and it still won’t start, it’s time to check the compression.

Key Takeaways:

Fuel is King: Use fresh, properly mixed fuel.
Spark Plug Matters: Inspect, clean, and replace regularly.
Prime with Precision: Master the primer bulb technique.
Choke with Care: Use the choke correctly for cold starts.
Compression Counts: Check compression if all else fails.

Next Steps:

Review Your Fuel Storage: Ensure you’re using fresh fuel and storing it properly.
Inspect Your Spark Plug: Clean or replace your spark plug if necessary.
Practice Your Priming Technique: Get comfortable with the primer bulb.
Master the Choke: Understand how to use the choke for cold and warm starts.
Consider a Compression Test: If you’re still having trouble, consider a compression test.

Don’t be afraid to experiment and learn from your experiences. Every chainsaw is a little different, and what works for one person may not work for another. But with a little patience and perseverance, you can tame that Stihl MS170 and get it running like a champ. And remember, safety first! Always wear appropriate safety gear and follow the manufacturer’s instructions. Now get out there and make some firewood!

Stihl MS170 Starting Tips (5 Pro Hacks for Tough Ignition)