Small Engines (Lawn Mowers, etc.): homelite timberman 45 18, adjustment screws, air leak

Question
runs wide open only ,throttel ok ,carb. has plastic H L screw stops, never saw this before. saw looks fairly new.can i remove the stops? & readjust carb.  idle screw backed way out no change.have some experience w/small engs. hope you can help.

Answer
The carb almost has to be sticking wide open.  It is possible there is an air leak but still the carb would have to deliver fuel for the engine RPM to increase.

Have you removed the carb?
The adjustment screws would (should) not cause the problem.
Let me know if you removed and inspected the carburetor.
Eric