I have a kobelco sk 150 lc III, it started acting up while running, the rpms starting falling off a than start increasing out of the blue. Than it didn't want to start had to go back and mess with pump lever a lil bit, after running it for awhile finishing up so small tree work. When you go and turn key off it won't shut-off machine, have to use the hydraulics to help kill it. I've owned it for 3 years now and have been running B11 soy-deisel with power serve in cold weather, not sure if it matters but some say construction equipment doesn't like soy. Just looking for some help of where to start. thanks.