Don't waste your time cleaning the carb,
Standard practice by mower shops and
backyard mechanics is to clean carbs.
Fact is once gummed up they never will
run properly and are just another trip to
the mower shop waiting to happen.
It's a waste of time to attempt to clean it.
Carb probably isn't more than $45-$60
If you don't know the part number
most can be found online by doing a
search within Google.
Briggs and Stratton have pdf files on
all their engines available for viewing and
download on their website.
Hope this helps.