I have a Toro 286e (Koohler 26hp with efi) and while mowing, it will nearly stall out (sounds like ignition shutoff) but before stopping completely, it recovers and off we go again. Only later, the process repeats itself. So far - plenty of fuel; no apparent ignition problems; no shifting on seat (or other ignition interlocks); no apparent loose connections; etc. New fuel filter at start of season (<15 hours ago). Mower has 311 hours and is well maintained. Any ideas on what to look for out there?