if it was me, I would drain gas tank, or remove and clean and try new clean gas, add some seafoam to it as well maybe.
a new spark plug.
and just see if that gets it up and running.
IF not, pull the carb off, and do a rebuild/cleaning to it.
and you should be fine.alot of the older motors are pretty simple, also clean or replace the air filter too.

none of the above is very hard to do, just takes a little time, so, you might try doing so yourself and save a bunch on paying someone else to do so?