How to Check the RPMs on a Husqvarna Chainsaw

Start the machine and allow it to warm up for two or three minutes.

Clamp the alligator clip leading from a portable electronic tachometer to the plug lead close to the spark plug.

Locate the three screws marked "L," "T" and "H" protruding through the left of the engine cover just past the chainsaw handle.

Put a flat-head screwdriver in the screw marked “L.” Turn the screw clockwise until it stops. Press the chainsaw gas trigger and then release it. If the engine has poor acceleration or erratic idling, turn the “L” screw counterclockwise while pressing and releasing the trigger until smooth, even idling and rapid acceleration is achieved.

Monitor the tachometer gauge and insert the screwdriver into the screw marked “T.” Turn the screw clockwise until the chain starts to rotate at just over 3000 RPM. Turn the screw counterclockwise until the tachometer shows a reading of 2700 RPM and the chain stops rotating. This step is critical - a too low idling speed causes the chainsaw to stall, and a too high idling speed engages the centrifugal clutch and starts rotating the chain.

Press the gas trigger and accelerate the saw to its maximum speed while monitoring the tachometer. If the reading climbs above 9000 RPM and the saw “whistles,” the fuel/air mixture is too lean. Turn the “H” screw counterclockwise until the tachometer reading drops below the 9000 RPM mark and release the trigger.

Press the trigger once more. If the engine starts to “4-cycle” by missing alternative beats at high speed and you notice black smoke coming from the exhaust, the fuel/air mixture is too rich. Turn the “H” screw clockwise slowly until the smoke disappears and the chainsaw fires evenly and runs smoothly at high speed.