Stihl MS-181 Bogging Down When Cold

[thclimer]

My Stihl MS-181 saw seems to have developed a strange behavior that when its cold, it bogs down when you try to increase the throttle.

When its cold, it starts fine and idles without any issues until you try to increase its speed.

If you gently ease into progressively giving it more throttle and let it warm up (20-30 seconds at approx. 1/8 throttle) the bogging/stalling issue becomes less and less. Once you can reach full throttle a few times and continue to warm it up, maybe another 20-30 seconds the bogging issue goes away. Once its warm you can shut the saw off and restart it without any issues. If you let it cool for a few hours, the same behavior of the saw bogging down begins.

I have replaced the fuel filter, air filter and spark plug without any change.

Any ideas? Thanks in advance.

 

[Vintage Engine Repairs]

Open the L screw 1/8 turn increments until it improves.

 

[thclimer]

I'll give that a try.

However, I'll need to let it cool as I was running it earlier this morning as I removed the gas check valve/vent cap to ensure it was not clogged.

 

[VincentFR]

I had the same issue with my MS211.
Choke linkage was a little bend and the choke isn't fully open.

 

[thclimer]

Adjusting the L screw was a success!

Thanks so much for the recommendation.

 

[Vintage Engine Repairs]

You’re welcome

 

[lone wolf]

Open the L screw 1/8 turn increments until it improves.

Good call.