Question for gear heads

[Tree-Taylor]

Hey folks,

I'm not the mechanically inclined type but lately I've been trying to improve my knowledge on the subject.

I've got a question that is probably obvious but I haven't been able to find the answer. What mechanism causes the chainsaw to start in high idle? I'm guessing that choking the chainsaw also opens up the throttle valve to create a greater vacuum, and by hitting the throttle lever it resets the valve to the normal idle setting.

Any input would be appreciated. Thanks

 

[Reach]

Hey folks,

I'm not the mechanically inclined type but lately I've been trying to improve my knowledge on the subject.

I've got a question that is probably obvious but I haven't been able to find the answer. What mechanism causes the chainsaw to start in high idle? I'm guessing that choking the chainsaw also opens up the throttle valve to create a greater vacuum, and by hitting the throttle lever it resets the valve to the normal idle setting.

Any input would be appreciated. Thanks

“ I'm guessing that choking the chainsaw also opens up the throttle valve to create a greater vacuum, and by hitting the throttle lever it resets the valve to the normal idle setting.”

This is correct, on some saws at least. Late model Stihl saws, for sure. Some other saws, especially older models, have a separate throttle lock to set the high idle necessary for cold starting a saw.

 

[Tree-Taylor]

“ I'm guessing that choking the chainsaw also opens up the throttle valve to create a greater vacuum, and by hitting the throttle lever it resets the valve to the normal idle setting.”

This is correct, on some saws at least. Late model Stihl saws, for sure. Some other saws, especially older models, have a separate throttle lock to set the high idle necessary for cold starting a saw.

I was thinking more in terms of my Husqy saws, but now that I think of it, you have to engage the throttle trigger in order to choke a 200t. Makes a lot more sense now.

 

[Bart_]

A second effect is if your fuel system isn't primed and full the first running can be lean causing even higher revs till the mixture normals out.