The Complete Overview of Stihl MS170 How to Start
The **Stihl MS170** starts differently than a four-stroke engine or even a modern EFI chainsaw. Its two-stroke design relies on a precise blend of fuel, air, and ignition timing—all orchestrated by your hands. The process begins *before* you touch the starter cord. A cold engine needs a richer fuel mixture, which is why the choke plays a pivotal role in **Stihl MS170 how to start**. But here’s the catch: the choke setting isn’t static. It shifts as the engine warms, and misjudging the transition can leave you with a flooded motor or a stubbornly unresponsive pull-start. What makes the MS170 unique is its balance of power and accessibility. Unlike industrial-grade Stihl models, this one is built for the backyard, the farm, or the weekend warrior—but that doesn’t mean it tolerates sloppy technique. The starter cord, for instance, requires a sharp, controlled motion. A lazy pull won’t build enough compression, while an aggressive yank can snap the cord or strain your wrist. Then there’s the throttle—often overlooked in basic guides. Holding it too long during startup can cause the engine to backfire, while releasing it prematurely starves the combustion chamber. These nuances are what turn a chainsaw from a tool into a precision instrument.Historical Background and Evolution
The **Stihl MS170** traces its lineage back to the post-war era when Andreas Stihl revolutionized chainsaw design with his 1926 invention—a portable, gasoline-powered tool that could fell trees with surgical precision. By the 1970s, Stihl had perfected the two-stroke engine, which became the backbone of portable chainsaws. The MS170, introduced in the late 1980s, was a refinement of this technology: lighter than its predecessors, with a more efficient carburetor and a 17-inch bar optimized for home use. Its design philosophy was simple: reliability for the masses without sacrificing performance. What sets the MS170 apart from earlier models is its carburetor tuning. Early Stihl chainsaws often required manual adjustments via screws, but the MS170 introduced a pre-set carburetor—easier for users but still demanding in terms of fuel quality. The "how to start" process evolved alongside this: as engines became more refined, the margin for error in choke and throttle management shrank. Today, the MS170 remains a benchmark because it embodies Stihl’s core principle: **a tool should start reliably the first time, every time**, even in suboptimal conditions.Core Mechanisms: How It Works
At its core, the **Stihl MS170** operates on a two-stroke cycle where fuel and oil mix in the crankcase, then enter the combustion chamber during the upstroke. The spark plug ignites this mixture, creating the force that drives the piston down and powers the chain. The choke’s role is to restrict air intake, enriching the fuel mixture for cold starts—a critical step in **Stihl MS170 how to start**. But the choke isn’t just a binary switch; it’s a graduated control. On a cold engine, you’ll pull it fully closed. As the engine warms, you’ll gradually open it, a process that requires observation. The throttle, meanwhile, controls the air-fuel ratio during the pull-start. When you yank the cord, the throttle should be held *slightly* open to allow air in, but not so far that the mixture becomes too lean. The sweet spot is a balance: enough air for ignition, but enough fuel to sustain combustion. This is where most users stumble. A common mistake is holding the throttle too long during the pull, which can cause the engine to "gear up" too quickly and stall. The key is a **sharp, decisive pull** followed by an immediate throttle release—only to re-engage it once the engine catches.Key Benefits and Crucial Impact
The **Stihl MS170** isn’t just a chainsaw; it’s a testament to engineering pragmatism. Its two-stroke design delivers unmatched power-to-weight ratio, making it ideal for tasks ranging from limb pruning to small tree felling. But the real advantage lies in its **how to start** reliability. When properly maintained, this chainsaw starts on the first pull, even in cold weather—a feature that separates it from competitors who require multiple attempts or preheating. For professionals, this means less downtime; for homeowners, it means fewer expletives. What’s often overlooked is the long-term impact of correct startup procedures. A flooded engine can wash oil out of the crankcase, leading to premature wear. A misadjusted throttle can cause carbon buildup on the piston, reducing efficiency. Mastering **Stihl MS170 how to start** isn’t just about immediate success; it’s about extending the tool’s lifespan by years.*"A chainsaw is only as good as its first pull. The MS170’s simplicity is its superpower—once you respect the process, it rewards you with decades of service."* — **Mark R., Stihl Certified Technician**
Major Advantages
- First-Pull Reliability: With proper fuel mix (50:1 ratio) and choke management, the MS170 starts consistently, even in sub-zero temperatures.
- Durability: The two-stroke engine, when maintained, outlasts many four-stroke alternatives, thanks to robust piston and cylinder design.
- Lightweight Power: Weighing just 11 lbs, it’s easier to maneuver than heavier models while delivering 2.8 HP of torque.
- Low Maintenance: Fewer moving parts than four-stroke engines mean less wear over time, reducing long-term costs.
- Versatility: The 17-inch bar handles everything from firewood to brush clearing, making it a one-tool solution for most tasks.
Comparative Analysis
| Stihl MS170 | Husqvarna 440 |
|---|---|
|
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| Best for: Homeowners, weekend warriors, small-scale logging | Best for: Light-duty tasks, users who prefer a quieter cut |
| Weakness: Oil separation in fuel over time (requires fresh mix) | Weakness: Less power for heavy-duty work |
Future Trends and Innovations
The two-stroke engine, while reliable, is facing obsolescence in favor of four-stroke and electric alternatives. Stihl has already introduced models like the MS 261, which combines a four-stroke engine with electronic ignition—eliminating many of the manual adjustments required in **Stihl MS170 how to start**. However, the MS170’s enduring popularity stems from its simplicity and cost-effectiveness. For now, it remains the go-to for those who prioritize raw power over modern conveniences. Looking ahead, expect to see more hybrid systems that retain the two-stroke’s simplicity while adopting electronic controls for better fuel efficiency. But for the foreseeable future, the MS170’s startup ritual—choke, throttle, pull—will remain a rite of passage for chainsaw enthusiasts.
Conclusion
The **Stihl MS170** isn’t just a tool; it’s a partnership. Its startup process, though seemingly straightforward, is a dance between mechanics and human intuition. Skip a step, and you’ll pay for it in stalls, backfires, or worse. But when executed correctly, the reward is a chainsaw that starts effortlessly, cuts aggressively, and lasts for years. The key isn’t memorizing steps—it’s understanding the *why* behind each action, from the choke’s role in fuel enrichment to the throttle’s impact on combustion timing. For those who treat their MS170 with the respect it deserves, the payoff is clear: fewer headaches, more uptime, and a tool that feels like an extension of your hands. And in a world of disposable power tools, that’s a legacy worth preserving.Comprehensive FAQs
Q: Why does my Stihl MS170 keep stalling after starting?
The most common causes are a dirty air filter, improper fuel mix (too lean), or a clogged carburetor. Check the air filter first—if it’s dirty, clean or replace it. Then verify your fuel ratio (50:1 gas to oil). If the issue persists, the carburetor may need cleaning or adjustment.
Q: Can I start the MS170 without pulling the choke all the way?
No. A cold engine requires a fully closed choke to enrich the fuel mixture. Partial choke settings can lead to poor combustion or flooding. Only open the choke gradually as the engine warms (typically after 2–3 pulls).
Q: What’s the correct throttle position when pulling the starter cord?
The throttle should be held **slightly open** (about 1/4 turn) during the pull-start. This allows enough air for ignition without starving the engine. Release it immediately after the first pull, then re-engage it once the engine catches.
Q: How often should I change the spark plug?
Every 100 hours of use or annually, whichever comes first. A fouled spark plug is a leading cause of starting issues. Use a **NGK DCPR7E** or equivalent and gap it to 0.020–0.025 inches.
Q: What happens if I use the wrong fuel mix?
A mix that’s too lean (too much gas) causes overheating and pre-ignition, while a mix that’s too rich (too much oil) fouls the spark plug and washes oil from the crankcase. Always use a **50:1 ratio** (2.6 oz oil per gallon of gas) for the MS170.
Q: Why does my chainsaw smoke when starting?
Excessive smoke usually indicates a rich fuel mixture or oil separation. Check your fuel mix and ensure the oil is fully dissolved in the gas (shake the fuel can for 30 seconds before use). If the issue persists, the carburetor may need servicing.
Q: Can I start the MS170 in cold weather without preheating?
Yes, but you must use **Stihl-branded oil** and ensure the fuel is fresh. Cold temperatures thicken oil, so pre-mixing fuel 24 hours ahead helps. If the engine still struggles, a **Stihl pre-heat spray** can assist, but avoid overusing it—it can gum up the carburetor.
Q: How do I know if the carburetor needs cleaning?
Signs include rough idling, poor acceleration, or the engine dying when you release the throttle. Over time, varnish and debris build up in the carburetor jets. If cleaning doesn’t resolve the issue, the carburetor may need professional tuning.
Q: Is it safe to leave the MS170 running for extended periods?
No. Prolonged idling can cause overheating and increase wear on the piston and cylinder. If you’re not actively using the chainsaw, turn it off. The MS170 is designed for intermittent use, not continuous operation.
Q: What’s the best way to store my Stihl MS170 long-term?
Drain the fuel system completely, run the engine until it stalls (to clear residual fuel), and store it with a fresh spark plug and clean air filter. Use a fuel stabilizer if storing for more than 30 days, and keep the chainsaw in a dry, temperature-controlled environment.
