Stihl 180 How Many Revolutions Per Minute
Why it may be necessary to adjust the carburetor even if it seems to start and work? Carb adjustments should be optimal.
In general, the carburetor has a very important effect on the operation of the chainsaw, it is its "brain" indicating how much air and fuel mixture to feed into the cylinder and in what proportion. If the mixture is “rich”, that is, the fuel in it will be more than it should be, then as a result we have a loss of power, deposits on the walls of the cylinder and piston. Which in turn can lead to failure of the chainsaw. In turn, the “poor” mixture, which has more than normal air in its composition, also leads to loss of power, insufficient lubrication of the CPG, scuffing and possible “jamming” of the engine. Optimal settings of the carburetor of the chainsaw allows you to get maximum power, extend the life of the engine, ensure minimal emissions into the atmosphere!
Poor and rich mix
A little more about the "poor" and "rich" mixtures.
A “rich” mixture is a fuel mixture in which the amount of fuel supplied to the carburetor exceeds the norm. In this case, the fuel does not have time to burn out completely and less energy is produced than with the optimal ratio of fuel to air. Partially unprocessed fuel enters the muffler, then the chainsaw smokes heavily.
There is an excess of air in the “poor” mixture, which is also not good, as it has its drawbacks. Namely: insufficient energy during a flash (which means loss of power as a result), excessive heating of the cylinder due to insufficient lubrication and high revolutions, which leads to scoring, and not far from the engine “jamming” there.
Chainsaw Carb Adjustment
Video: Stihl 180 How Many Revolutions Per Minute
Most chainsaws have three adjustment screws on the carburetor. In order about each:
- T. Idling screw. The idle screw is responsible for the throttle position when the throttle grip is fully released. If the throttle valve is not open enough, the engine will stall with the handle released as the valve will shut off the flow of the fuel mixture. If the throttle valve is opened by a larger amount than it should be, then the chain will rotate, which is strictly prohibited by safety precautions when working with a chainsaw.
- L-screw low speed adjustment. This screw controls the amount of fuel in the fuel mixture when the chainsaw is idling. If the amount of fuel is large, the engine will stall under load, if the fuel is not enough, the result will be overheating of the engine, badass, and so on
- H-screw adjusts high revs. It is responsible for the amount of fuel in the mixture during operation of the chainsaw. If this adjustment is configured for more fuel, the engine runs “unacceptably” and smokes, and if it is less, we get too high revs and overheating.
Carb Adjustment Step by Step
- Check the condition of the air filter. We remove it and either clean it or change it. If the air filter is clogged with dirt and sawdust, the operation of the chainsaw will not be normal.
- Check the condition of the muffler. It should be clean and unbroken. Read more about cleaning the muffler HERE.
- Before you start adjusting the carburetor, you should fill the fuel tank at least half.
- If the chainsaw is able to start, then she should let it work for several minutes so that it warms up. If the adjustment is carried out “cold”, then the mixture will be re-enriched after heating.
- To begin the adjustment, it is necessary to adjust the idle speed-screw L. It is highly desirable to have a tachometer, then we focus on 2700 rpm. If not, then we need to find the highest idle speed. In this case, the chain should not rotate. If it still turns (the chain is finite, not the Earth), then we achieve its stop by rotating the T screw. The sound of the chainsaw should be like listening to the file below.
https://benzopilatut.ru/wp-content/uploads/2016/01/ Chainsaw- on-idle-way wav
- We adjust the high revolutions. screw H. If we rotate it clockwise then the revolutions will increase, and if counter-clockwise. fall. We twist it until there are dips in the ignition. After that, we turn it about one fifth of a turn. The sound of the chainsaw when working at maximum speed should be the same as when listening to the file below.
https://benzopilatut.ru/wp-content/uploads/2016/01/ Chainsaw-maximum- revolutions.wav
- Check how the chainsaw is gaining momentum. She must dial them smoothly and quickly. If the revolutions grow slowly, then slightly turn the screw L.
If you still have questions, write in the comments or better in the VK group.
Remember that the optimal carb adjustment is: