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?

Correct Answer: Option B — The temperature of the fuel from the preheater should be gradually reduced after switching over the three-way valve.

Under USCG National Maritime Center examination standards, the accepted correct answer is: The temperature of the fuel from the preheater should be gradually reduced after switching over the three-way valve..