Stihl ms 201 tuning up but is missing.

[spudulike]

Any ideas spud to check you seem like you know what your doing with tuning and getting the best from a saw?

 

I'm pretty much with Gardenkit on this, probably fuel/carb related.

 

Personally I would strip the carb, boil it in the ultrasonic cleaner at 50 degrees for an hour, check the welch plug is sealed, check the needle valve is holding pressure, check the gauze filter is clear and then reassemble and try again.

 

The symptoms in your case (Barrie has already done these checks) could also be caused by a lightly scored piston or an airleak from a split impulse or manifold causing an air leak.

 

My usual path is pressure/vac test, check compression and then work on the carb if OK - I would check the carb internal gauze filter as one of the first checks - a common part to get blocked and cause the saw to have lack of power in the cut but not free running.

[GardenKit]

To be honest, the one I am dealing with has beaten me. Its just in the last few days, had the piston and pot upgraded under warranty at a Stihl service centre (being only an 'approved Stihl dealer' they do not allow major warranty work to be done by me)

They were told about the bogging down issue and asked to investigate, repair and report, even if that work was not covered by warranty. I was willing to pay, as I was getting nowhere.

The saw came back on Monday and was no better at all.

It is now packed up ready to go back again!