Stihl MS180 will start but dies when you throttle?

I have an MS180 that does the same thing.Before you fiddle with anything carb related be sure to check your spark arrester is clear and check your air filter isnt blocked.Fixes mine every time.

Dave
August 2013

Poor acceleration
Setting of low speed screw too lean Check basic carburetor setting, correct if necessary
High speed screw too rich Check basic carburetor setting, correct if necessary
Inlet needle sticking to valve seat Remove inlet needle, clean and refit
Diaphragm gasket leaking Fit new diaphragm gasket
Metering diaphragm damaged or shrunk Fit new metering diaphragm
Manifold damaged Install new manifold

Tony
February 2012

Simon,
On the bar side of the saw there will 2 or 3 holes in plastic case. These holes are the carburetor mixture screws. They are labeled as follows - H=High Speed Jet, L=Low Speed Jet and LA=Idle Speed. If the saw runs at idle and when you pull the trigger, as it seems this is the case, it dies unless you let off in time. Your L screw is too LEAN. Turn this "Jet" Screw out (counter-clockwise), 1/8 - 1/4 of a turn. Do this at the same time pulling the trigger on an off until the saw starts to wants to speed up and reach full throttle speed. If it doesn't and you have turned it more than 1.5 turns or more then you have something stuck in the jet, your internal screen is plugged, your in-tank filter is plugged or your fuel line is collapsing because it is old and very soft and is getting sucked flat when the carburetor is demanding more fuel. Hope this helps. I will check back for a response to see if this helped you.

Luggnutt
February 2012