Check the muffler for internal plugging of the spark arrestor, and inspect the top of the port in the cylinder for carbon build-up. Check the air filter for plugging. Make sure the bar and chain are being oiled properly and that the chain can be moved freely by hand (and that the teeth are sharp). The chain should be tight enough to not droop from the lower side of the bar, but not so tight that it is difficult to turn by hand. Make sure that you are using the proper fuel/oil mixture (and fresh fuel) and that you are using chainsaw oil, not automotive engine oil. Finally, you can try adjusting the 'H' needle on the carburetor to obtain "4-stroking" when the engine is at full speed, but immediately "2-strokes" when cutting wood. Hope this helps!
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Check the muffler for internal plugging of the spark arrestor, and inspect the top of the port in the cylinder for carbon build-up. Check the air filter for plugging. Make sure the bar and chain are being oiled properly and that the chain can be moved freely by hand (and that the teeth are sharp). The chain should be tight enough to not droop from the lower side of the bar, but not so tight that it is difficult to turn by hand. Make sure that you are using the proper fuel/oil mixture (and fresh fuel) and that you are using chainsaw oil, not automotive engine oil. Finally, you can try adjusting the 'H' needle on the carburetor to obtain "4-stroking" when the engine is at full speed, but immediately "2-strokes" when cutting wood. Hope this helps!