I "inherited" a non-running Craftsman 32cc (4 stroke) weedwhacker. Previous owners placed it out in the garbage, having already purchased a new one.
The problem? Of course dirty carb (Walbro WYL ) and fuel line related. Cut to the chase, I cleaned ALL carb innards, replaced all the rotted/disintegrating fuel lines and fuel filter with brand new.... drilled out the tiny main jet to .0135", increased the float level just a bit using my Walbro float level gauge. Verified/checked valve clearances fine at .006" (where have i read that VC are critical to check?

) and soda blasted the spark plug to perfectly clean it. I believe I've covered all the bases....its now an instant starter/runner!
Now just needs new "cutting lines" and I'll put it into service immediately. Cost so far? Zero.....all parts came from my stock.....now a keeper fo' sure!
I've ordered a carb kit as the fuel pump diaphragm was quite hardened, its simply time for a new one. And a new primer bulb, the original has also hardened and frankly, split. I custom cut another, used super glue to glue it right over the breaks......to temporarily repair until new arrives.
Note edited to add further details.