[Crowbob]

2-stroke engines smoke, even when the fuel is mixed correctly. That means exhaust gasses and particles get, well, exhausted through the spark arrestor as is on most 2-stroke engines on yardequipment. So when you throttle up the combusted air/smoke cannot exit and the engine acts like it's not getting air when actually it is not exhausting it.

After checking fuel lines, gaskets, spark plug, carb, air/fuel adjustments, pure gas, blah blah blah and it still acts like it's starving for air------clean the arrestor.

Or clean it first and avoid doing all that other stuff.

If it still doesn't work, give it to your son-in-law to mess with and then throw out eventually.