The situation when your favorite instrument Husqvarna 137 refuses to start, often takes the owner by surprise. This popular model is valued for its reliability, but even time-tested equipment requires competent maintenance and timely intervention. Failure to start can be caused by many factors: from a simple lack of fuel in the tank to serious problems with the piston group.
Before panicking or taking the saw to a service center, it is necessary to conduct an initial diagnosis. In most cases, the problem can be solved independently, having a minimum set of tools and basic knowledge of the structure of two-stroke engines. Systematic approach will help you quickly identify a node that requires attention.
In this article we will examine in detail the main causes of engine failure, methods for eliminating them and preventive measures. You'll learn how to test for spark, tune your carburetor, and why the quality of the fuel mixture is critical to the performance of your tool.
Primary diagnostics and testing of the fuel system
The most obvious, but often ignored reason is the lack of fuel or its poor quality. If the saw was left idle for more than a month, the old mixture could separate or lose its octane properties. Gasoline freshness is a key factor for a stable launch.
Check the fuel filter, which is located inside the tank. Over time, it becomes clogged with tarry deposits, which prevents the normal flow of fluid to the carburetor. It is also worth inspecting the fuel hoses for cracks and air leaks.
It is important to ensure that the air damper Choke works correctly. During a cold start, it should completely shut off the air supply, enriching the mixture. If the mechanism is jammed, the engine will not receive the required concentration of fuel for the first burst.
- 🛢️ Check the presence of fuel in the tank and its freshness (the shelf life of the mixture is no more than 2 weeks).
- 💨 Make sure that no vacuum plug has formed in the tank (open the lid and listen to the hissing sound).
- 🔍 Inspect the fuel filter for contamination and replace it if necessary.
⚠️ Attention: Never leave a chainsaw with a full tank for long-term storage. Old gasoline turns into resin, which permanently cokes the carburetor channels and damages the membranes.
If everything is in order with the fuel supply, but the saw is still silent, we move on to the next diagnostic stage. Often the problem lies deeper, in the ignition or compression system.
Ignition system: spark plug, coil and clearances
Lack of spark is the second most common cause of starting problems. To check, you need to unscrew the spark plug and inspect its condition. Soot, black color of the electrodes or wet deposits will indicate problems with the combustion of the mixture.
Sometimes the problem is solved by simply cleaning or replacing the spark plug. However, if the new spark plug remains dry after repeated starting attempts, it is worth checking the high-voltage wire and the ignition coil itself (magneto). The gap between the flywheel and the coil must be strictly 0.2-0.3 mm.
The best way to check the spark is to touch the spark plug to the engine metal (ground) and pull the starter. A bright blue spark indicates the system is working properly. A dull or reddish spark indicates a weak discharge or breakdown.
- 🔌 Unscrew the spark plug and check the gap between the electrodes (should be about 0.7 mm).
- ⚡ Conduct a spark test: it should be stable and bright blue.
- 🧹 Clean the spark plug with a metal brush or replace it with a new one (NGK or Champion recommended).
If there is a spark, but the engine does not catch, the spark plug may be flooded. In this case, you need to dry the cylinder by cranking the engine with the throttle open and the spark plug removed.
Carburetor problems and mixture adjustments
The carburetor is the heart of the engine, and the slightest malfunction in its operation leads to a failure to start. If the chainsaw Husqvarna 137 it won’t start, the screws may have gone out of factory settings L, H and T. Screw L responsible for low speed and starting, H - for high, and T - for idling.
A common problem is contamination of the jets or sticking of the needle. Even a microscopic speck can disrupt the patency of the canals. In such cases, complete disassembly, ultrasonic cleaning and blowing of all channels with compressed air is required.
It is also worth paying attention to the carburetor diaphragms. Over time, they become tanned and lose elasticity, ceasing to pump fuel correctly. Replacing the carburetor repair kit often solves the problem of unstable starting.
⚠️ Attention: Before adjusting the carburetor screws, make sure the engine is warm. Cold adjustment will lead to incorrect operation when hot and may cause overheating of the piston.
When setting up the carburetor for the first time, tighten screws L and H until they stop (without fanaticism), and then unscrew them 1-1.5 turns. These are the starting values for most Husqvarna saws.
Compression and condition of the piston group
Low compression is a serious diagnosis and often means major repairs are required. Without sufficient pressure in the cylinder, the fuel mixture simply cannot ignite. You can check the compression with a special compression gauge or manually by plugging the spark plug hole with your finger.
The reasons for a drop in compression can be different: wear of the piston rings, scuffing on the cylinder, damage to the crankshaft seals or burnout of the piston. If, when cranking with the starter, you feel ease of movement and lack of characteristic resistance, the problem is here.
A defect in the crankshaft seals also leads to air leaks, which leans the mixture and impairs starting. Checking the seals requires removing the crankcase and using a special leak test.
| Symptom | Possible reason | Elimination method |
|---|---|---|
| No resistance when jerking | Destruction of the piston group | Replacing the CPG (cylinder-piston group) |
| Strong air leak | Wear of crankshaft seals | Replacing seals and checking tightness |
| Compression below 8 atm | Occurrence of rings or scuffing | Defective cylinder, replacement of rings |
| The saw smokes and stalls | Burnt out piston or exhaust port | Engine overhaul |
How to check crankcase leaks?
To check the tightness of the crankcase, plug the inlet and outlet holes, create excess pressure (about 0.5 atm) and immerse the assembly in water or lubricate the joints with a soap solution. The appearance of bubbles will indicate the location of the leak.
Muffler and exhaust system
A muffler clogged with carbon deposits is a common reason why the saw starts up and immediately stalls or does not develop speed. The combustion products of the two-stroke mixture settle on the walls of the muffler and in the exhaust channel, narrowing the passage.
If the exhaust gases cannot escape freely, fresh mixture will not enter the cylinder. This leads to “choking” of the engine. It is necessary to remove the muffler, burn off the carbon deposits or soak it in a solvent, and also clean the exhaust port in the cylinder.
In some cases, carbon deposits can clog the spark arrestor (mesh) inside the muffler. Removing it or thoroughly cleaning it restores normal traction and starting.
- 🔥 Remove the muffler and visually assess the degree of contamination of the channel.
- 🧹 Mechanically remove large pieces of soot with a metal brush.
- 🧪 In case of severe contamination, soak the parts in kerosene or a special cleaner.
Regular maintenance of the exhaust system prolongs the life of the engine and keeps its power at a high level.
Seasonal problems and storage
Many starting problems occur after winter storage. If you preserved the saw incorrectly, pockets of corrosion could form inside or the seals could dry out. Before the first launch of the new season, careful preparation is required.
Check the condition of the air filter. A filter clogged with sawdust blocks the air supply, making the mixture too rich. Blow out the filter or replace it if it is very dirty.
It is also worth checking the chain tension and the condition of the tire. Although this does not directly affect engine starting, excessive load when attempting to cut can stall a poorly warmed-up engine.
☑️ Preparing the saw after winter
Compliance with storage rules ensures that next season Husqvarna 137 will start the first time.
Frequently asked questions (FAQ)
Why does the chainsaw only start when the choke is closed?
This indicates that the engine is not getting enough fuel when the throttle is open. Most likely, the carburetor is dirty, the fuel filter is clogged, or the tightness of the fuel hoses is broken, which leads to a lean mixture.
How often do you need to change the fuel filter in a chainsaw?
It is recommended to check the condition of the filter every season. If you use the saw professionally, you should replace it every 50-70 hours or whenever there is a sign of loss of power.
Can I use motor gasoline for Husqvarna?
No, for two-stroke engines Husqvarna It is recommended to use high-octane gasoline (AI-92 or AI-95) with an octane number of at least 90. The use of low-quality fuel leads to detonation and overheating.
What should I do if, after cleaning the carburetor, the saw still does not start?
It is necessary to check the compression and condition of the crankshaft seals. Perhaps the problem is not in the carburetor, but in air leaks through the cuffs or wear of the piston group.
90% of problems with starting the Husqvarna 137 chainsaw are solved by replacing the fuel filter, cleaning the carburetor or replacing the spark plug.