Small Engines (Lawn Mowers, etc.): Stihl FS44 String Trimmer, air passages, combustion chamber

Question
I aquired a Stihl FS44 from a co-worker that ran when put away. Then later
did not start. I checked the plug for spark and have it. Fueled with new fuel
and primed with the primer. Tried to start it and it did not fire. Put a little fuel
in the cylinder and still no fire. Remover the cover and cleaned the hi and low
idle screws and removed both side plates from the carb and blew out. I then
put a cap of fuel directly into the carb intake and still no fire. What else can I
do?

Answer
One thing to check would be to exhaust ports of the engine are they plugged with carbon?  If so clean them.

If no fuel is getting into the combustion chamber remove the carburetor and see if fuel will flow from the tank if it does that part of the system is okay if you have to loosen the fuel cap to get it to flow replace the fuel cap.  if the fuel flow is restricted replace the fuel filter.

Next check the insulator block the block between the carburetor and the cylinder it should not you warped.  next disassemble the carburetor use a tag wire clean all the little air passages and fuel passages in the carburetor. be sure the screen inside the carburetor is clean.  be sure the fuel metering lever is set properly and there is not a hole in the diaphragm.  Reassemble the carburetor and try again.  The plug should get wet if the system is working.  be sure the throttle is set to wide open throttle and the chole is operating and that the on off switch is working.  somewhere in this process you should find your problem