Should you run chainsaw at full throttle?

A chainsaw screaming at full tilt can hard to take, does make you wonder does it really need to run this fast.

Should a chainsaw run a full throttle? A chainsaw is designed to run at full throttle. A large tree, many times the thickness of the bar will require full throttle.

On this page you’ll learn why full throttle is in most cases the safest.

Lawn mower on fire

Full or None

why are 2 stroke engines noisy?

A two stroke engine unlike a lawn mower engine revs at much higher rpm. It can do this because a two stroke engine is designed to power the piston (aka power stroke) on every second cycle of the engine.

A lawn mower and your car engine powers the piston only on every forth cycle of the engine.

The increased power strokes of a chainsaw allows the engine to rotate at far greater rpm than a four stroke engine, and it can get up to speed far more quickly.

The speed and increased power strokes (explosions) creates a lot more noise than a four stroke.

Full throttle or not?

Running a chainsaw at half throttle isn’t advised for two main reasons:

  1. Personal safety
  2. Engine protection

personal safety

    Timber should be cut on full throttle for safety reasons. The risk of kickback is far greater when a saw contacts timber at lower speeds.

    What is kickback? Kickback happens when a saw tip contacts the work-piece and violently throws the saw blade upwards and back-ways towards the operator.

    It isn’t always this violent and your saw is fitted with a chain brake to help prevent injury.

    You can help prevent kickback by:

    • Applying full throttle before entering the work-piece
    • Avoiding contacting the tip of the bar on the work-piece
    • Use the bottom of the bar, close to the saw body to cut
    • Support the work-piece when finishing the cut
    • Reduce throttle when finishing out the cut

      You’ll find most modern hobby saws will have been designed to reduce kickback. They will have features such as low kickback chains and low kickback bar and all modern saws will have a chain brake fitted.

      But it always better to be prepared, having the right kit is really important, hoodies with dangling strings or torn clothes can easily be grabbed by the blade.

      Wear tight clothing, chaps work great. Good solid work boots, and hard hat if working under falling branches.

      I encourage all saw owners to enlist on a training day, your local hardware store will likely know where these type day courses are held.

      Chainsaw carburettors

      Carburettor tuned at full

      engine protection

      A two stroke chainsaw engine is designed to run at full tilt, it’s at it happiest on full song. Running at half throttle for anything other than short periods isn’t advised.

      All engines need lubrication to help reduce friction and cool internal engine components. Without oil, an engine will stop dead, and isn’t repairable.

      A chainsaw, as you know doesn’t have regular engine oil like a car. Instead the oil is mixed with the gas, without oil in the gas mix, the little two stroke engine will seize.

      When a saw is at full throttle its carburettor is tuned to supply the engine with a rich gas/oil mix. Meaning the engine is well protected from the risk of seizing.

      However, when running at half throttle, a saw runs leaner, and by leaner I mean it’s getting less gas/oil mix proportionally and therefore less protected.

      A saw can run at half throttle, but it’s not designed to work here for long periods, doing so risks damaging the engine.

      You might find this page useful, it lists common Chainsaw parts and tools I use in the workshop.

      2 stroke oil

      2 stroke oil

      Related Questions

      Why does my chainsaw die at full throttle? Your saw dies at full throttle because it is running too lean. Top five causes of a lean running engine include:

      1. “H” jet needs to be adjusted 
      2. Dirty carburettor
      3. Blocked gas filter
      4. Worn diaphragm
      5. Worn needle valve
      Auto Technician and Writer at | Website

      John Cunningham is an Automotive Technician and writer on Lawnmowerfixed.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write "How to" articles that help fellow gear-heads with all aspects of mechanical repairs, from lawn mowers to classic cars.