At Idle
By Tim Ard, Forest Applications Training, Inc.

You know it is always good to idle down and take some time to rest. This is especially true when operating chainsaws. When you start to tire it's time to sit down and take a break. Fatigue is understood to be one of the major causes of accidents and injuries with equipment operators.

A chain saw should idle sometimes too. Like when you let off the throttle, the chainsaw should stop rotating the chain. You see, when the chain is turning you stand a higher chance of cutting something. You don't want it to be a part of your body.

Chain saw's have a centrifugal clutch system that is a major part of it's operation. When the throttle is released, the clutch disengages and the chain is released from its drive system. The clutch has weighted shoes and springs that are activated by the rotation of the engines crankshaft. The weights are centrifugally thrown outward at above idle rpm to engage the sprocket drive drum to turn the chain loop on the guide bar. When the throttle is released the chain should stop rotating.

If the saw chain doesn't stop turning it greatly increases your chances of the reactive forces of push, pull or kick-back coming into play unexpectedly. 

If the chain turns at idle it may be caused by one or more of the following:

1. The saw's idle screw (T or LA) is set too high.
2. The centrifugal clutch springs are weak or broken.
3. The roller bearing on the crankshaft is seized or dirt bound.

Some of the common problems caused by a clutch that doesn't work properly:

1. The saw is hard to start because of the resistance of the chain.
2. The engine dies when the throttle is released.
3. The chain brake band is worn or over heated.
4. The operator is exposed to a higher risk of injury.
5. Saw control is greatly decreased for accurate cutting.

So when you take a break your chainsaw should also. Never, never operate a chainsaw that doesn't rest when you do... When you let the engine idle, the saw chain should too.

Remember - review your operator's manual regularly and put on your PPE before starting your chainsaw work. 

Good Sawing!
Tim Ard

More information on chain saw operation and safety can be found at Tim's website