:smt100In my 2000 410 da I have 2 7.4 mags they both sound and proform well but the starboard engine after it warms up ,the oil pressure slowly drops from 40 to 20. So I changed the oil with 25/40 as recomended by merc. and the oil pressure then stayed at 40 lbs. for the rest of the day wich was only a couple more hours of opperation. Then the next time I used the boat was a week later, the oil pressure was back to dropping to 20 lbs. after warm up. Does any one know whats going on or any ideas???? I have a bad feeling about this, hopeing i'm wrong. Gus