Stihl MS 170 throttle linkage keeps coming loose at carburator end

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godfreydanials

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I have a Stihl MS 170 that is about 4 years old, with very little useage. Recently the hooked end of the throttle linkage started popping out of the slotted lever on the carburator. I have reconnected it twice and it just popped out again. I don't see any retainers or anything to keep this linkage captured. I thought I would just bend the open slot closed on the carb lever, but that metal is very hard and would probably break before it bent.

How can I prevent this rod from coming loose?

Does anyone have a diagram of this linkage, or a PDF service manual?
 
If there's any plastic in the linkage chain then the opportunity for wear is always present. I can't visualize this setup but here's one cheap band-aid: Cinch a small plastic tie wrap (a.k.a. cable ties, come in sizes from tiny to huge, at any auto parts /Radio Shack /etc.) around the two parts. If no binding, then maybe a reasonable fix?
 
I have a Stihl MS 170 that is about 4 years old, with very little useage. Recently the hooked end of the throttle linkage started popping out of the slotted lever on the carburator. I have reconnected it twice and it just popped out again. I don't see any retainers or anything to keep this linkage captured. I thought I would just bend the open slot closed on the carb lever, but that metal is very hard and would probably break before it bent.

How can I prevent this rod from coming loose?

Does anyone have a diagram of this linkage, or a PDF service manual?

PM (private message) sent
 
there was a revision done on these probably 2-3 years ago, they re designed it to hook the other way and we haven't had a problem since. ill have a look tomorrow if there was a change in part number or just a running change over
 
there was a revision done on these probably 2-3 years ago, they re designed it to hook the other way and we haven't had a problem since. ill have a look tomorrow if there was a change in part number or just a running change over

Never heard of any revision, been parting them out for 5 years now, working on them a lot longer

View attachment 231725
231725d1333301983-ms170-005-jpg


The return spring on the throttle rod on the carb and the spring on the trigger keep the rod tight

View attachment 231726

231726d1333302028-ms170-006-jpg

To remove the throttle rod, squeeze the trigger, and hold the throttle on the carb open.
 
Last edited:
Tell me more...

Fish,

I do have a return spring on the carb throttle shaft, but the linkage is just flopping around. Do you have a picture, or can you describe what I am looking for on the trigger end of the linkage for a spring? I will go out to the barn in the morning and have a look. I took down a big willow today with the Husky and don't have enough left in me to go back out tonight. I would like to use the 170 to cut the small stuff up.

Thanks for your help, I really appreciate it.
 
The spring on the trigger end is in the black plastic handle part, you need a new throttle rod if both springs are working....

Folks like to bend **** before thinking...........................................
 
there was a revision around April 2009. View attachment 232046

Thanks guys for the jpegs. I took the throttle rod out and sighted down the end of it. The flat link that goes through the trigger was about 15* off of perpendicular to the vertical end below the hook at the throttle plate. I grabed both ends with pliers and twisted the rod clockwise until they appeared to be square. I ran the saw for a couple of hours yesterday with no problems. If it comes off again, I will find a new style throttle rod to replace this one.
 
Simple as this
 

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