A kit would be the cheapest way to go...........
Or is the carb missing from the mower ??
That style carb has the brass seat for the needle..... I change those seats pretty often....... They erode and cause leakage of gas to the oil......... It's a pain in the butt to change those seats....................
But It's not a problem for me since I do it 10 to 15 times a spring / summer............