Ryobi RLT254CDSO - Bump Knob Hard to Turn; Lubricant Drips from Muffler

Bump knob hard to turn. Screw threads dirty or damage. Clean threads and lubricate with grease - if no
improvement, replace bump knob.
Lubricant drips from mufer. Operating the product at part
throttle.
Operate the product at full throttle.
Lubricant/fuel mixture is
incorrect.
Use fresh fuel and correct synthetic 2-stroke lubricant mix..
Air lter is dirty. Clean per instruction in “Maintenance” section.