Stihl MS250 wont idle

G

ghost1

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• Jan 20, 2017 / Stihl MS250 wont idle

• #1

Need some help. I'm working on a Stihl MS250 chainsaw that won't idle. I have done the following and not sure what else to check.

Has compression
Replaced carb, and plug
Checked fuel line, impulse line, and intake boot for leaks
Adjusted idle, high and low fuel screws

Both carbs have same symptoms.

 

BlazNT

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• Jan 23, 2017 / Stihl MS250 wont idle

• #2

Does it run but not idle?

 

D

deminin

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• Jan 23, 2017 / Stihl MS250 wont idle

• #3

Check the muffler....the spark suppressor screen can get partially plugged on any chainsaw, especially if you have been running the oil mixture a bit more than recommended.

 

upupandaway

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• Jan 24, 2017 / Stihl MS250 wont idle

• #4

Excessive leaking shaft seals will also do this.

 

B

bertsmobile1

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• Jan 24, 2017 / Stihl MS250 wont idle

• #5

upupandaway said:

Excessive leaking shaft seals will also do this.

Click to expand...

Shaft seals usually make it hard to start from cold or after a prolonged period of storage .
Then it becomes easier to start when you are using it every weekend ( cutting firewood ).

 

upupandaway

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• Jan 26, 2017 / Stihl MS250 wont idle

• #6

bertsmobile1 said:

Shaft seals usually make it hard to start from cold or after a prolonged period of storage .
Then it becomes easier to start when you are using it every weekend ( cutting firewood ).

Click to expand...

Bert, the condition I am referring is where there is serious damage to the seal. Slight leaking that you imply where the lower chamber can build enough pressure and still idle. My suggestion damage\wear\worse leak is beyond this and thus not enough lower chamber pressure at idle (die) but enough pressure at high to keep running. Using it more frequently won't fix this condition. Just a suggestion to the user's problem.

 

BlazNT

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• Jan 26, 2017 / Stihl MS250 wont idle

• #7

We lost the OP a long time ago.

 

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ghost1

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• Jan 28, 2017 / Stihl MS250 wont idle

• #8

UPDATE:

It was the piston/rings. One ring was seized and piston/head was scored. The seal on one side was very loose on shaft. Replaced head, piston, rings and seals. It runs like a new one...
Thanks to all.