Stihl ms 170 choke won’t stay engaged

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CFar45

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I was recently given a used ms 170. Have only used it for about 1-2 hours but have started it maybe a dozen times. The choke won’t stay engaged in the half choke position. It stays engaged in the full choke position and releases as it should when throttle trigger is pulled. I am pulling throttle trigger when setting the choke to on position. It seems that it was engaging in the half choke position initially, but now will not. The plastic bar of choke assembly appears to be seated in place and the spring appears to be in place. Any advice/thoughts?
 
Ok… so writing the post got me thinking about it more, so went out and took a look at it. When the choke lever is depressed to the fullest extent possible, it does not release when throttle is pulled. I was assuming it would release from full choke with application of throttle and that this position was “beyond” full choke. I’m now realizing that this position is likely the full choke position and that it must be manually taken out of full choke position. The choke position from which it releases with application of throttle is likely the half throttle position. Unless this description is incorrect, I think I’ve figured it out… duh. Feeling stupid, but really thought choke previously released from both full and half position with throttle. Prob just wasn’t paying attention and only ever used half choke.
 
You have worked it out, congrats.

The starting procedure is to squeeze throttle trigger and push the choke lever fully down.
Pull on the cord until you hear the slightest cough then immediately move the lever upwards to next position. Pull until it starts (at a very fast idle) then use throttle to keep it running at a slower idle until it runs smoothly and responds to the throttle. Cut wood.

if the saw is warm sometimes the first choke position is not needed.
 
You have worked it out, congrats.

The starting procedure is to squeeze throttle trigger and push the choke lever fully down.
Pull on the cord until you hear the slightest cough then immediately move the lever upwards to next position. Pull until it starts (at a very fast idle) then use throttle to keep it running at a slower idle until it runs smoothly and responds to the throttle. Cut wood.

if the saw is warm sometimes the first choke position is not needed.
 
Thanks for confirming! I should’ve known. Just wasn’t paying attention/thinking through this new to me saw. Thanks for not beating me up over this 🙂
 
Thanks for confirming! I should’ve known. Just wasn’t paying attention/thinking through this new to me saw. Thanks for not beating me up over this 🙂
I can understand your way of thinking. Some of the older Stihl saws had a Separate kill switch and a choke only toggle and the operator present feature that when you squeezed the throttle it released the fast idle catch. Took me a while to get comfortable with the later STUFF
 
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