not be higher than 17-18 cSt. If a change-over is made from HFO to DO while the engine is running, there will be a short loss of power, but the engine will keep running. A change-over to HFO while the engine is running on DO will cause misfiring/engine stop due to too low temperatures of the metal part in the fuel feeder line and injection pumps. The fuel oil pump discharges to the high- pressure pump header through a duplex filter. Surplus oil is returned to the diesel oil service tank or the fuel oil system depending on the position of the double 3-way valve.An electrically operated shut-off valve on the suction side of the fuel oil pump shuts off the fuel oil supply in case of an emergency. The valve is controlled from the Remote Emergency Operating Panel.