How To Start A Stihl 250 Chainsaw

Stihl MS250 Unboxing

Engine jammed

Quite often there is a situation when the saw worked and stalled abruptly, the cause of which was the engine jamming, which in turn occurred as a result of a broken piston skirt, destruction of the crankshaft bearing, protrusion of the piston pin cork ring or a fracture of the piston ring.

A jammed engine can be easily identified by pulling on the starter cord. In the case when the starter does not turn, most likely, it has jammed, and further repairs are possible only at the service center.

Broken fuel line

During the operation of the chainsaw, vibration occurs, which can cause damage or breakage of the fuel line of the chainsaw. In this case, the chainsaw will stall and it will be impossible to start. To diagnose a malfunction, you need to conduct an inspection and determine the presence of fuel leaks.

Why does a chainsaw start badly?

• fuel and air filters;
• reduced compression;
• carburetor adjustment;
• spark plug;
• ignition coil;
• the gap between the ignition coil and the flywheel;

Let’s consider each reason in more detail.

Fuel problems

As with the difficult hot start option, problems in the fuel system can affect a cold start or inability to start. Carburetor adjustment, fuel filter and line contamination are all reasons that cause start-up difficulties.

Diagnose the fuel system, this is the first thing you need in case of difficult cold start.

It is worth paying attention to the quality of the fuel, because when using a mixture of gasoline and oil, in which there is a small amount of water, starting can be significantly difficult or impossible.

The mixture must be used sufficiently fresh, because when storing gasoline diluted with oil for more than a month, its properties are lost and it complicates starting, both on a cold and hot engine. For this reason, gasoline can burn poorly.

Chainsaw won’t start

Every person who is familiar with a gasoline tool knows that sometimes the equipment works intermittently, or it may stall at one moment and will not start again. There are a lot of reasons why the chainsaw does not start, we will try to consider the most common of them.

Potential interruptions occur due to engine problems. But I would not recommend disassembling it immediately. It is better to look for the problem using the simplest option.

It is very important to consider the quality of the fuel. If the mixture is improperly prepared or has deteriorated over time, even reliable tools such as Urals or Husqvarna 145 will not work. The instructions should indicate the proportions and the specific oil for your chainsaw.

Another common problem. during startup, the user pours a candle. It must be checked if it is completely dry, then the fuel does not go into the cylinder.

Fuel and air filter

Contamination of the main filter elements of the chainsaw, negatively affects its operation.

For example, a dirty air filter will not fully supply air to the carburetor, which will affect the quality of the air-fuel mixture and the normal starting of the engine. Contamination of the fuel filter will make it difficult or even shut off the gasoline supply to the carburetor and make the engine impossible to operate.

How to start the saw after long periods of inactivity

I can’t start the chainsaw after a long period of inactivity. Such comments can be found on the forums dedicated to the repair and operation of saws. Let’s figure out how to start a chainsaw after a long downtime.

The fact is that it is necessary to take care of a successful start after a downtime and properly prepare the saw for storage. According to the manufacturer’s instructions, before storing, it is necessary to drain the fuel from the tank, then start the engine and burn off the fuel in the fuel system.

Preparation is necessary so that the carburetor membranes do not stick together during storage. Performing this simple operation will allow you to successfully start the saw after long-term storage.

It is much easier to start the chainsaw six months after idle time, if just before starting, through the spark plug hole, add 1. 2 ml of the fuel mixture to the cylinder. This can be done with a syringe.

What happens at the moment of priming fuel with primer, and how it helps to start the saw more efficiently?

At the moment of starting the saw without a primer, several movements of the starter are carried out only so that the fuel pump, under the action of an impulse from the saw crankcase, pumped fuel into the carburetor.

A pump installed in the fuel line allows you to manually pump gasoline into the carburetor without unnecessary movements with the starter. The effect of this action is obvious, the saw will start much faster.

Many owners of gasoline-powered tools mistakenly believe that a hand pump can overly pump fuel into the carburetor and, for this reason, will flood the candle. This is fundamentally wrong, since the system is able to circulate around. Excess gasoline from the carburetor will be directed, through a dedicated hose, back to the tank.

Cold Starting a Stihl MS250 After Not Using It For Years

There is no need to use a primer on a hot chainsaw, since there is enough fuel in the carburetor to start.

How to start a Stihl chainsaw

All Stihl chainsaws are equipped with two-stroke engines, the cold start of which has a similar algorithm. But there are models on which additional equipment is installed that allows you to start the saw without excessive efforts. For this reason, the algorithm for starting them may differ slightly.

Let’s take a look at how to start a regular saw and how the process differs from starting a modified model.

• We start Stihl 180
• We start Stihl MS 180 C
• We start Stihl MS 211 C-BE
• What happens when the primer is pumped up, and how it helps to start the saw more efficiently?
• How to start a chainsaws with a decompression valve
• How to start the saw after long periods of inactivity
• Outcomes

We start Stihl MS 180 C

The device of this model, in comparison with the previous one, has some differences in the trigger mechanism, but it does not carry any changes in the triggering algorithm. The fact is that the ErgoStart system is installed in the Stihl 180 C, which, due to an additional spring installed in the chainsaw starter, reduces the engine resistance when starting.

How to start a chainsaws with a decompression valve

Before starting a Stihl chainsaw on which a decompression valve is installed, you must turn it on. It should be noted that there is no decompression valve on the Stihl 250 saw.

After the first flash has passed, the valve is set to normal operation, respectively, after the engine control lever is set to the open position of the choke and starting continues, the decompression valve must be pressed again.

The valve operation is schematically shown in the figure below.

In fact, the valve does not make starting faster, it just simplifies the process and makes it more comfortable, because for during launch, a person will have to apply much less effort.

A saw with a decompression valve, whether the engine is cold or hot, must be started using the valve to relieve the cranking force of the engine. This will significantly increase the life of the starter and reduce the number of torn laces, since it is installed on chainsaws with a large cylinder volume and, accordingly, compression.

We start Stihl MS 211 C-BE

The fuel supply system in the Stihl MS 211 C-BE chainsaw is additionally equipped with a manual fuel pump, which makes it easier to start the chainsaw on a cold.

The instruction for starting this model of the Stihl chainsaw contains one additional point, which is that before starting the chainsaw on a cold one, it is necessary to pump fuel into the carburetor using a pump. Further, the instruction does not differ from starting Stihl 180 and follows the same algorithm.

We start Stihl 180

In order to start a Stihl 180 chainsaw on a cold one, you must follow the algorithm specified by the manufacturer in the instructions for the Stihl 180 chainsaw, namely:

• Turn on the ignition and set the engine control lever to the lowest position (in this position, the air damper of the Stihl 180 carburetor blocks the air from the air filter, and the throttle valve is fully open, thus the fuel mixture is enriched);
• Pull the starter handle several times until the first flash passes (the flash signals that the fuel mixture has entered the cylinder and the saw is ready to start);
• Set the control lever one position up from fully lowered (in this position, the air damper opens, and the throttle remains in the same position as before);
• Pull the starter and start. The saw will start and run at higher rpm due to the fact that the throttle valve is open as much as possible. To set the damper to idle, you must press the gas trigger and immediately release, the tool immediately normalizes the speed.

The Stihl MS 180 chainsaw, as standard, does not have any additional devices that can facilitate starting.

Below you can see how to start a Stihl 180. The video reflects in detail all the main points, and the author’s comments allow you to understand the whole process to the smallest detail.

Starting a Stihl chainsaw almost always follows the same algorithm, except for those cases when a decompression valve and a fuel primer are additionally installed on the chainsaw. These gadgets are designed to facilitate the startup process and do an excellent job of their functions.