First, check the exh. for a clogged spark screen and or a clogged exh. port at the cyl. Pull the plug and check condition and gap.
Then make sure the fuel lines are not split/cracked etc. and the filter is flowin.
If the above are OK , then its time to look into the carb, possibly adj the HS needle, if it has one.
It ain't rocket science!
'Course if yer house has more wheels than yer truck...
" Old age ain't for sissies "