Oil Leak New Engine

[Jprevat]

Ok seems like something new is going on. My oil pressure is now reading about 50 psi cold idle. As it warms up the pressure seems to stay the same. Thinking that was a little high I switched out the oil to 5w30 just to see if the gauge changed. It didn't. When I pull the oil fill cap I can see oil flowing but I also see a small bubble here and there.

Is my oil pump cavitating? Am I going to have to pull this dang thing again?

 

[Lou C]

When you say it warms up are you running the boat in the water or on the water hose? Because if on the hose, it will not heat the oil enough to see the pressure reading drop as it usually does after running on plane. On my old 4.3 I'd get 40-50 cold idle, then after running at speed and slowing down to idle, I'd get about 20. However, on the water hose, it never dropped below 40. I've used straight 30, 40, and the Merc 25/40. I would not use 5w/30 in a marine application. So if you're getting this 50 psi running on the water hose I'd say you have nothing to worry about.

 

[Jprevat]

That is on the hose. I ran it this morning in the river with 30 sae and it warmed up I started hearing a slight knock. I pulled it out of the water, checked the oil, all was fine and dandy. Waited about an hour cranked it back up and the knock was gone. I was thinking the rebuilt motor may have tighter tolerances than a factory spec long block so I figured I'd try a little lighter oil for the moment.

 

[Jprevat]

Ok so I took it back out and I honestly think I may just have to live with a small noise. I may just be paranoid from having to pull it so often but it jumps up pretty quick and cruises comfortably at a minimum planing speed of 28 mph at 2k rpms. I haven't topped it out but I think it will do every bit of 45.

My oil pressure did drop down to about 40psi at idle once it warmed up to 160* but I think my gauge is wrong. It says I'm at 70 psi at 28 mph and at 37 mph with no change at all.

Best of all though, I no longer have a leak!

Thank you guys for all the help but please feel free to tell me if any of my assumptions above are off base.