| When running a large, dual fuel, main propulsion diesel engine on heavy fuel, which of the following precautions should be observed when switching from heavy fuel oil to diesel oil? |
| A) The temperature of the fuel from the preheater should be gradually reduced after switching over the three-way valve. |
| B) The diesel oil must never be allowed to mix with the heavy fuel. |
| C) The heating steam to the preheater should be increased as soon as the diesel fuel passes through the three-way valve. |
| D) The heating steam must be secured before the diesel oil passes through the three-way valve. |
