Stihl 4 Stroke FS 130 running problem solved.

My FS130 4 stroke brush cutter uses oil in the fuel mix. When it began losing power and dying, I tried all the obvious options: Spark plug, fuel filter, carb kit, exhaust screen, then tappet clearances. No joy.
I even cut slots in the 3mm mixture screws to remove them and adjust the low and hi speed mixtures.

In desperation, after noticing fuel around the carb, I removed the air filter. It ran great after that.

The constant soaking with fuel eventually leaves the dense part of the factory air filter choked with oil.

A good couple of degreasing sprays, both sides of the filter are a temporary fix, or replace with a foam filter.

[weobeyjesus]

Thanks mate. I have a pole saw I was about to take to the shop because it was running terrible this morning. Looked in the air cleaner and it's full of fuel. It rolls onto it's side on the ute, that's probably what caused it. Cheers

[kennytheguitarfanatic]

Your gas tank vent is bad the tank can't vent so fuel enters the small tube in the air cleaner housing and gets on your air filter. Common problem on stihl 4 mix engines the vent is cheap and easy to replace in your gas tank. Had same problem with my 4 mix

[reelMn]

Make sure you dry out the air filter completely before reinstalling.