oil pressure has always been rite at or around 60psi. I have noticed the last couple times it has been down around 40 and even lower, especially at idle. Oil pump?

Oil pumps seldom ever fail for the life of an engine. Oil pressure for the most part is determined by bearing clearances. What oil weight are you running and do you think it may need changing. Best weight would be a 15-50 or 20-50.

10-30 mobile one. I changed oil in both motors a month ago. I check it before i start it everytime and it seems to be very clean. Is 10-30 not a good weight for boats?

if pressure is down, clearances are opening up some. i would run a straight 40 or 50. if you can't get synthetic in that weight, a PA grade. pennzoil or q-state...

+1

10-30 is not good enough for the heat and load on a marine engine. Most popular oil around here seems to be the Mobile 1 15-50. You can get it in the 5 qt. jugs at Wally World. You could use straight 40 or 50 but personally I prefere the multi-vis to assure good lubrication during starting cold especially if running a larger pan.

Could i have done any damage running the 10-30? Do the clearences open up due to wear?

I ran Mobile 1 15w50 in my Chris Craft Stinger. Not sure if it is rated for marine use or not but we had to pull one engine down as a "pink" rod broke in half in the center (weird, I know). There was no measurable wear on the engine after 300 hours. Currently I use Mercury full synthetic 25w-40 in my Fountain. Oil pressure will fall off at idle especially if you come off of some fast running. I would not recommend running 10-30. Do you have an oil temp gauge?

Yes clearances will become larger with wear but were' talking thousandths here. 40lbs of pressure isn't that low. May just be the oil breaking down when hot. At this point there's nothing you can do except change to good stuff and run it.

Yes i have oil temp gauges. Now that you mention It that engines oil temp always got hotter when running the boat over 4grand. I never understood why but never thought much of it.