Small Engines (Lawn Mowers, etc.): rough running jd l110, caps plugs, adjustment screw

Question
trying to help my brother get his lawn mower running good.
it will start and run fine at low rpm but when you increase to full throttle it will run then start acting like it is running out of gas and want to die.
we have changed oil and filter,new spark plug, new fuel filter,new air cleaner.i even drained the tank and blew out the fuel line.and sprayed some carb cleaner through the carb,and it is still doing the same thing.
any ideas?

Answer
ken
what is happening is the carburetor is starving for fuel, some dirt may be clogging the high speed port. You may have to take the carburettor apart and rebuild & clean it out. Just remember where all the parts go,use a digital cam or write it down it is easy to forget what goes where and how it is installed.
If you have the following symptoms


Engine hunts (at idle or high speed)
Engine will not idle
Engine lacks power at high speed
Carburetor floods
Engine starves for fuel at high speed (leans out)

Then these fixes may help.
Adjust main mixture adjustment screw; some models require finger tight adjustment. you can also Adjust idle mixture screw
Check for bent choke and throttle plates
Adjust control cable or linage, to assure full choke and carburetor control.
Clean carburetor after removing all non-metallic parts that are serviceable.
Check inlet needle and seat for condition and proper installation
Check sealing of welch plugs, caps, plugs and gaskets
Adjust governor linkage.
Adjust float settings if float type carburetor
Check float shaft for wear and float for leaks or dents
Check diaphragm for cracks or distortion and check nylon check ball for function if available.
Check sequence of gaskets and diaphragms for the particular carburetor being repaired.