Hello I have a 2003 727 Z Track lawn mower with approximately 650 hrs on it, and it has been running increasingly rough, trying to make it through mowing season 😃. I have replaced fuel filter and loosened gas cap, no change. I have pulled plugs and replaced but did not gap them (no gauge) . I noticed one plug nice and dry BUT the other one quite wet! And in general dirtier looking. No noticeable oil leaks on outside of engine from blown gasket for instance. It’s sputtering when I give it throttle and doesn’t seem to get up to full RPM when I’m mowing, no real symptoms at idle. Kind of surging and sputtering in general and getting worse when mowing! What do you guys suggest I check next?