Does the chain saw start abnormally?

It is a common phenomenon that the chain saw has difficulty starting or cannot be started during use. How do you deal with this problem?If you want the chain saw to start normally, you should ensure the following points:

[Important content】

Compression: To maintain optimal cylinder pressure, there should be no loss of compression within the cylinder.

Ignition system: At the optimal ignition time, the ignition system should produce a strong spark.

Fuel system and carburetor: The air-fuel mixture should be supplied at an optimal mixing ratio.

Therefore, when the chain saw has difficulty starting or cannot start, we will troubleshoot the problem one by one according to the above factors:

1 Check Compression: Diagnosis starts externally and ends internally

External conditions → tightening conditions → cylinder → piston → crankcase

First check whether the spark plug is tightened, and then turn the starter wheel (pull the starter) by hand. When it passes the top dead center (slowly pull the starter 1-2 turns), it feels more laborious (can be compared with a new machine), and After turning over the top dead center (after the machine rotates a few times), the starting wheel can automatically rotate through a larger angle (it will continue to rotate without pulling the starter), indicating that the compression is normal. If the piston rotates past the top dead center quickly or easily, it means that the cylinder compression force is insufficient. The problem lies in: the engine oil problem causes cylinder wear or cylinder pull; the cylinder block and crankcase gasket are leaking.

2 Circuit Problems: Diagnosis Starts at Exit and Ends at ImportSpark plug → spark plug cap → switch → high voltage, ground wire and switch wire → ignition coil → flywheel

If the compression is normal, there is no explosive sound in the cylinder (no sound) when starting the chain saw, and the gas discharged from the muffler is moist and smells of gasoline, which indicates that there is a fault in the circuit system. At this time, the spark plug should be removed (check the spark plug gap 0.6 ~0.7 mm), connect the spark plug to the high-voltage wire, with the side of the spark plug very close to the metal part of the machine body, and quickly pull the machine to see if there are blue sparks. If not, first check whether the spark plug cap is damaged, then remove the spark plug, directly use the high-voltage wire end to saw the metal part of the body about 3mm, pull the starter, and see if there are blue sparks jumping over the high-voltage wire. If not, it means there is a problem with the high-pressure package or flywheel.

3. Check the oil system: starting from the inlet and ending at the outlet

Fuel tank cap → Fuel → Exhaust valve → Fuel filter → Fuel pipe → Carburetor → Intake negative pressure pipe

If the circuit system is normal, it is time to check the fuel supply system. If there is no explosion sound in the cylinder when starting, the exhaust pipe is weak, and the gas is dry and has no gasoline smell, it most likely indicates that there is a problem with the fuel supply. Check whether there is enough fuel in the fuel tank, whether the fuel filter is seriously blocked, whether the fuel pipe is broken and leaking, and whether the carburetor is blocked. If these checks are all good and you still can't start, you can remove the spark plug, pour a few drops of gasoline into the spark plug hole (not too much), then install the spark plug and start the chain saw. If it can start and run for a while, it means the carburetor is clogged inside. You can disassemble the carburetor for cleaning or replacement.

41-None of the 3 situations

If everything mentioned above is good, you should consider whether the startup environment temperature is too low.

Maybe because the machine is too cold, the gasoline is not easy to atomize and it is not easy to start. At the same time, it is also necessary to consider whether the crankcase has poor sealing due to damage to the oil seal. When the ambient temperature is low, the damper should be closed a little smaller. When the ambient temperature is high, the damper should be fully opened before starting.

5. Gasoline oil ratio causes failureIf the fuel ratio of the chain saw is not good or there is too much carbon deposit in the muffler, it will also cause the chain saw to be difficult to start or fail to start. Clean it frequently to remove dust from the muffler, air filter, and body. The wrong grade or poor quality of gasoline and engine oil will also affect the starting of the machine. They should be configured and selected according to the requirements in the chain saw manual.

Startup methods and techniques

The direction and technique of the starting pull cord and the starting speed (how fast you pull the starter) also have an impact on the starting of the chain saw.

What should I do if the chain saw can start normally but the speed cannot be reached or the gas pedal stalls?Please continue to investigate

Fuel:

1. Check whether the air filter is clogged, clean or replace it;
2. The fuel filter head is clogged, just replace it;
3. Incorrect fuel usage, use correct fuel;
4. The carburetor adjustment is wrong. Reset the oil needle and re-adjust it (turn the H and L oil needles clockwise to the end, turn the H oil needle 1 and a half to 2 turns counterclockwise, and turn the L oil needle 2 and 2 and a half turns counterclockwise. , if the high speed cannot be reached, turn the H oil needle clockwise 1/8 each time; if the idle speed is normal and the throttle is turned off, turn the L needle counterclockwise 1/8 each time);
5. The carburetor is clogged, clean or replace it.

Exhaust system:

1. The muffler is clogged with carbon, scrape off the carbon deposit or use fire to remove it
2. The cylinder exhaust port is clogged with carbon deposits, scrape off the carbon deposits

Circuit:

The high-voltage package is damaged internally and needs to be replaced.