I had the same symptoms with mine last year. I changed everything with no change. Then I changed the fuel line, from the tank to the carb, and it now runs great. It may be as simple a fix as mine was. There are several YouTube videos on JD's losing power and how to fix. Good Luck.
Funny thing. That's exactly what I did with my L118 a couple months ago and it went from a dog to a swiss watch in no time at all.
Changing the line was an afterthought even, for some other basic maintenance I was doing on the thing!
