SERVICE BULLETINS SOB-17-01 20-MAR-17 ENGINE CONTROL MODULE (ECM) RECALIBRATION AND THERMOSTATINSPECTION - 40/50/60 HP EFI SOB-17-12 03-NOV-17 IMPROVED POWER TRIM POPPET VALVES (PO CHECK VALVES) SOB-18-01 25-APR-18 30/35/40/50/60 HP FOURSTROKE FUEL PUMP REPLACEMENT