I read the entire dialog on your problematic small engine.
I should have read here first....I spent way too much time dealing with a RYOBI weed whipper.
Carb kit...ran great for about ten minutes. Split fuel line after that, ran great for another ten. Leaky primer bulb allowing air to enter fuel line.
Something tells me that the "gas" I use is probably a root cause.
I will read deeper into these replies from now on.