stuff that makes gas last longer

[Tihol Tiholov]

Since we've moved to lawn mowers, lemme ask re: chainsaw issue.
Husqvarna 55, a bit over 10 yrs old, not mine.
Starts mosts times, revs like a monster on its own, chokes and dies, when
throttle squeezed.  Prior to that ran mid range, wouldn't rev high.  Newly
mixed gas, air cleaner flows well, flipped 180 deg. gasket on carburator to
engine intake port - gasket was in good condition.
Backgrnd: Owner used it all this time pouring gas and chain oil only.
Decided to clean the felt-made air filter with water, clogged it, I cleaned
it using a compressor.
Planning to open the tiny carburator, looking for dirt, never played with
those before.
Any ideas appreciated.

Thanks,

Tihol
Audiless for now