john deere 180 starving for fuel

i have a jd180 that is 23yrs old. it has been a good one.
i mow for about 45min. and then it seems to lose power
and i have to keep choking it to get it back to the barn.
any advice would be appreciated greatly.
thanks
engraver1

Have you checked the carb fuel bowl for sediment that could possibly be plugging passages ?
When was the last time your fuel lines were replaced ? They could be cracked and leaking air or breaking down inside causing dirt to be introduced into the carb.
Just guesses of course