I was having issues with my Tech 5hp engine on a mower. It was having a hard time side discharging heavier grass and a real hard time mulching. It would bog down and die pretty easy in heavier grass. I recently added MMO to the oil, ran it for about 5hrs total and noticed that it was running better. I changed oil to T6 after draining the MMO and it mulches like new. No issues with bogging down. Before I did the MMO/T6, I decarbonized the head, lapped/adjusted the valves thinking that would help, which did not. I have a little OCD when it comes to mower maintenance, so this mower has never been neglected. Suprised with the difference in performance after MMO and T6. Double dose of MMO in the gas for all of my OPE's.