Starting a chainsaw Stihl MS 180 when cold, it requires precise adherence to the sequence of actions, since ignoring the position of the throttle control lever or incorrect operation of the decompressor leads to “overflow” of the engine and the impossibility of starting. Unlike a warmed-up unit, a cold engine needs a rich fuel mixture, supplied only at the time of initial start-up, and any deviation from the algorithm disrupts the carburetor settings, making further attempts useless.
The main difficulty that owners face is a lack of understanding of the physics of the process: after the first “seizing” (the characteristic sneezing of the engine), it is necessary to immediately move the lever to the power stroke position, otherwise the spark will flood the spark plug with gasoline. Fuel mixture in this case, it stops igniting, and instead of starting, the user gets a wet spark plug and the smell of unburnt fuel, which requires a long drying of the cylinder.
In addition, a successful start directly depends on the condition fuel system and the quality of the mixture, which should not be stored for more than two weeks, since the oxidation of gasoline changes its flammability. If the starting algorithm is followed perfectly, but the saw does not start, the reason lies in the absence of a spark, a compression problem or a blockage of the air supply, which requires separate diagnostics of the components.
Preparing the fuel mixture and checking systems
Before pulling the starter, you need to make sure there is high-quality fuel, since Calm 180 extremely sensitive to octane number and amount of oil. Using pure gasoline without adding two-stroke oil will lead to scuffing of the piston group in a matter of minutes, so the proportion should be strictly 1:50 (20 ml of oil per 1 liter of gasoline) when using original oils Stihl.
Check that the fuel tank is clear and that there is no water at the bottom, as even a small amount of moisture in the carburetor will block cold starting. Condition is also critically important air filter: if it is clogged with sawdust, the engine will “suffocate” on a rich mixture and will not start, and a dirty filter often becomes the main reason why the saw stalls immediately after starting.
Storing the mixture
It is worth remembering that the finished gasoline-oil mixture cannot be stored for longer than 14 days. Over time, it loses its lubricating and ignition properties, which is especially critical for starting a cold engine, where the quality of the spark and mixture plays a decisive role. The old mixture may separate and the oil will settle to the bottom, which will lead to running on pure gasoline and overheating.
- ✅ Use AI-92 or AI-95 gasoline from proven gas stations, avoiding expired fuel.
- ✅ Shake the fuel canister thoroughly before each refueling to ensure even mixing of the oil.
- ✅ Visually assess the color of the exhaust: bluish smoke is normal, black smoke indicates over-enrichment of the mixture.
⚠️ Attention: Never leave the saw with a full tank for long-term storage. The fuel evaporates, leaving a tarry residue that clogs the carburetor jets, making cold starting impossible without complete disassembly and cleaning.
Cold engine starting algorithm
Startup process Stihl MS 180 is strictly regulated by the manufacturer and requires installing the saw on a hard surface with the right leg fixed in the handle. The first step is to enable chain brakes (the lever in front of the front handle is moved forward until it clicks), which ensures safety and prevents the chain from turning during the starter pull.
Next, you need to press the decompressor (if the model is equipped with this valve, which is typical for many modifications of the 180 series), which will reduce the compression in the cylinder and make the first jerk easier. At the same time, the throttle control lever is moved to its lowest position, and then raised one click up to the position 1 (cold start), in which the air damper completely blocks the air supply.
☑️ Checklist before the starter jerk
After preparation, gently pull the starter cord until resistance is reached, and then make a sharp and strong jerk upward. Do not pull the cord all the way, so as not to damage the mechanism, and do not release the handle suddenly - return it smoothly. As soon as the engine makes the first characteristic sound (“sneeze”), immediately move the control lever to the middle position 0.5 (working mode) and repeat the jerk.
Carburetor adjustment for starting problems
If the standard algorithm does not help, adjustment of the screw position is often required carburetor, responsible for the quality of the mixture at idle and during startup. On the model MS 180 often only one screw is available LA (idle), but some versions have access to the screw L (low speed), which directly affects the enrichment of the mixture during cold start.
Tightening the screw L clockwise makes the mixture leaner, and twisting it out makes it richer. If the saw does not start and the spark plug is wet, the mixture is too rich and the screw needs to be tightened slightly. If the spark plug is dry and there is a spark, you need to add fuel by unscrewing the screw a quarter turn counterclockwise.
| Symptom | Candle condition | Action with screw L | Result |
|---|---|---|---|
| Won't start, smell of gasoline | Wet, black soot | Tighten (clockwise) | Leaning the mixture |
| Stalls when pressing gas | Wet, soot | Tighten slightly | XX stabilization |
| Doesn't grasp at all | Dry, light | Unscrew (counterclockwise) | Mixture enrichment |
| Unstable | Brick color | Do not touch (norm) | Check filter |
Golden rule of adjustment: Never turn the carburetor screws on a running engine unless necessary. Lock the original position (count the revolutions when screwing it all the way) so that you can always return to the factory settings.
Diagnostics of the ignition system and spark plugs
Lack of spark is the second most common reason why Calm 180 does not start when cold, even with perfect adherence to the starting algorithm. To check, you need to unscrew the spark plug, put the tip of a high-voltage wire on it and press it with a metal skirt to the cylinder (ground), then pull the starter several times, watching for a spark to jump.
Soot color on spark plug is an excellent diagnostic tool: black soot indicates an over-rich mixture or poor oil quality, white soot indicates running a lean mixture and the risk of overheating, and a brownish-brick tint indicates proper engine operation. The gap between the electrodes should be 0.5 mm, and it can be adjusted, but most often the problem is solved by simply cleaning or replacing the spark plug.
If there is no spark even with a new spark plug, the problem may lie in ignition module (coil) or violation of the gap between the flywheel and the coil. The gap should be minimal (about 0.2 mm); to set it, they often use a sheet of paper folded in half, placing it between the flywheel magnet and the coil.
- 🔧 Check the integrity of the insulation of the high-voltage wire: cracks can lead to breakdowns to ground.
- 🔧 Make sure the Stop button is not shorted to ground, which permanently blocks the spark.
- 🔧 Clean the spark plug contacts from carbon deposits with a wire brush before reinstalling.
Eliminating engine overflow (flooded spark plug)
A common mistake when trying to start Stihl MS 180 is repeated jerking of the starter without switching the lever to the “warm start” mode after the first seizure, which leads to flooding of the combustion chamber with gasoline. In this case, the spark cannot penetrate the fuel layer, and the engine stops responding to any manipulation, requiring a “drying” procedure for the cylinder.
To eliminate overflow, you need to unscrew the spark plug, turn the saw over with the spark plug hole down and vigorously pull the starter several times to remove excess fuel from the cylinder. After this, wipe the spark plug dry, blow out the cylinder (you can use compressed air or just leave it open for 10-15 minutes) and put everything back together, starting again with the air damper closed.
Life hack for drying: If you don’t have a compressor at hand and don’t have time to dry for a long time, you can drop a couple of drops of pure gasoline directly into the spark plug hole after drying and sharply pull the starter. This helps dislodge any remaining oily film, but requires caution.
⚠️ Attention: When drying the cylinder with the starter, make sure that there are no open sources of fire nearby, as the fuel mixture leaving the muffler will ignite. Carry out the procedure in a well-ventilated area or outside.
Typical mistakes and their consequences
Many users ignore the need to warm up the engine after a successful cold start, immediately starting to saw under load. This leads to uneven expansion of the piston group parts, scuffing and rapid release piston out of order. Let the saw idle for 1-2 minutes, periodically pressing the gas so that the oil is evenly distributed throughout the components.
Another common mistake is starting the saw in the air (“floating”), which is strictly prohibited by the operating instructions. In this position, the body cannot be kept stable, the chain may touch the ground or foreign objects, and the inertia of the starter may cause injury to the operator or breakage of the handles.
It is also worth mentioning the mistake of using winter mode (if it is cold in your region) without adjusting the carburetor accordingly. Although MS 180 has a simple design, at temperatures below -10°C the standard mixture may be too “lean” for a cold start, requiring either the addition of gasoline to the mixture or the use of special additives.
Frequently asked questions (FAQ)
Why does Shtil 180 start and immediately stall?
Most often, the reason lies in the incorrect setting of the idle screw. LA or air leakage through the crankshaft seals. It's also worth checking the fuel filter in the tank: if it's clogged, there won't be enough gasoline to keep it running once the throttle is opened.
What kind of gasoline is better to pour into the Stihl MS 180?
It is recommended to use gasoline with an octane rating of at least 90 (AI-92 or AI-95). It is important that the fuel is fresh (not older than a month) and does not contain alcohol additives, which can have an aggressive effect on the rubber carburetor seals.
How often do you need to change the spark plug on a chainsaw?
With active use, it is recommended to change the spark plug once a season or after 100 operating hours. However, if carbon deposits form too quickly, the change interval should be shortened or the proportion of the oil mixture should be revised.
Is it possible to start the saw without a decompressor?
Yes, Stihl MS 180 It is possible to start without pressing the decompressor, but this will require significantly more effort, especially on a cold engine with high compression. Using a decompressor makes the pull easier and reduces the load on the starter and the operator's hands.