Small Engines (Lawn Mowers, etc.): Ryobi 790r 31cc engine carb adjust, speed jet, spark arrester

Question
When the engine is running with throttle open, it runs rough and doesn't reach high speed. When I open throttle fast the engine can die. It seems starved for gas. H & L screws on carb. Turning H screw out seems to improve, but not enough. Idle is ok. Any suggestions on proper screw setting?

Answer
Hi Russ,

The initial setting for the jets are: High speed = 1&1/2 turns out.  Low speed = 3/4 turn out.  If the high speed jet is much further out, try closing it a bit to give higher rpms.  If the jets don't help then the carb may need rebuilding or cleaning.  The spark arrester screen or muffler may be clogged also.

let me know how you make out.
Michael