Need help on how to protect the block. Came back from a day trip on Sunday. Engines ran solid. Shut them down. Came back the next day to flush with these: While the flush was going, the port engine would not start. Stopped the flush. Smartcraft said Port MAP input Hi. Thought the sensor was bad and that battery was the issue and used the emergency start (in hindsight perhaps not the best move), but the port engine would not turn over. Called it a night. Now I am thinking hydrolock, and that the pressure of the water during flush may have overwhelmed an exhaust gasket, or the gasket failed when the engine was shut down. And that the MAP sensor was correct. Will pull plugs and check oil today. Have read to add Marvel mystery oil to the 'wet' cyclinder(s) assuming that there is water in there to prevent rust. Questions: How would this oil be added to the cylinder since it is in a bottle? Is there some other spray in oil to be used?