Small Engines (Lawn Mowers, etc.): 4600LP green Machine blower, air filter assembly, adjustment screws

Question
Older machine but never used much. Will not rev past mid range. Fresh gas. Dirt in high speed jet? Restricted exhaust? How is the carb adjusted correctly? I assume one is idle, second is mid range and third is high speed. I have never touched the adjustments till today. I noticed one mixture screw is bottomed out.  
Thanks Glenn

Answer
If you have a spark arrestor on the muffler.  Remove it and clean all the debris from the spark arrestor is a screen that covers the muffler exhaust opening.  It would also make sense to remove the muffler and check the exhaust port for any obstructions.  Next would be a thorough cleaning of the fuel system remove the carburetor disassemble it and clean every air and fuel passages with a wire from a wire tie and blowout with carburetor cleaner or compressed air purchase a new carburetor kit from your dealer along with new mounting gaskets.  Install the carburetor kit per the instructions and set the in the inlet needle.  Turn the adjustment screws in until they lightly seat.  Reattach carburetor using new mounting gaskets attached throttle and choke controls.  Locate the fuel filter and be sure it is clean or replace it flush the fuel line with fresh gas.  Back flush the fuel tank at the point where the fuel line attaches.  Put fresh fuel and tank and opened adjustments screws at carburetor 2 turns.  Start the unit leaded warm-up and make final adjustments.  With throttle in wide-open position turn the high-speed adjustment screw in until the engine starts to falter then turn the screw out until the engine starts to flood and set it halfway in between.  Let the unit come to idle and do the same with the low speed screw.  Attach air filter assembly restart unit and make any necessary adjustments.  I hope this information helps please contact us if you need further assistance.