I took the unit in to dealer because the unit was just getting to be impossible to start. They tore the unit down and found that the valves were not seating due to buildup on them. This unit is one year old and probably has less than 250hrs on it. Kohler now says you must run 89octane in these engine, guess I missed that point in the manual. Just passing along what I am learning....looks like we will switch from 87 to 89 since all the trimmers should be 89.