The tell tale Ive seen on dyno when oil level is getting into the crank where I saw around a 10 hp drop was oil pressure got a little erratic at rpms and dropped some from getting whipped up/aerated was when you came off the pull, idle oil pressure would drop from about say 25/30lbs to about 15 and after letting engine sorta stabilize before shutting it off it would come back to normal in 15 to 30 seconds. At that point Im pretty confident oil was aerated/foamed up and had to sorta "regather", Ive also seen this on engines with crappy oil pans with no oil control. A customer brought a 440 sbc in with a cheap claimer pan on it, I asked him WTF he would run a 159$ pan on a engine with a 4" stroke, it clearly was foaming/whipping up the oil because it got twitchy from 5800 mup and would have that drop after pulling back then recover. he also had run of mill oil in it, we changed the oil to venom racing oil which has a anti foaming agent or whatever you call it in it, lowered level a quart, he picked up about 6 hp and it twitched about 60% less on top, he clearly needed a better pan fwiw.

Dry sump take care of this issue?

Ideally every marine engine would be a dry sump but the simple solution short of a dry sump is a good oil pan with amuch control as possible, preferably with a little more capacity then needed ran slightly lower then rating. On my 1100 hp blower engine in my 272 baja I had, I ran a 14 qt wet sump pan and usually ran it 1 or 2 qts low. Engine saw 6300 quite a few times and every time I freshened it I was looking at bearings that still looked like new fwiw

So going back to theWeingartner vid...i guess the next thing would be to have him fill the pan with the rated oil capacity and see where it levels out in the pan in relation to the crank and if it actually comes into contact with the crank or not....if not then there's something else going on for the power loss.
Im sure everyone does the measuring for pickup clearance...but ive never thought to measure for oil level in relation to crank bob-weights.....

Thats exactly what needs to be done

This is also interesting....never would have thought the oil flow would be that huge compared to temp....i mean i knew oil thinned out as it got hot but this is eye opening!

Interesting.

I seen that one too, they ran oil to point it was losing pressure on top picking up air in pump and gained 12/ 16 hp, not worth long term damage, added 4 quarts on top of that and lost 60 hp from best to worse.

What's the capacity of the Gen VI 502 MPI pan? Stated capacity from Merc with the filter is 7 quarts - with the filter, all the lines, and the cooler (but using the factory pan) I'm at 10 quarts to measure full on the factory dipstick. Oil pressure and oil temp are great. Good to go? Am I overfilling? Did Merc specify not using the full capacity of the pan? Just curious.

My engine was dyno'd 2 quarts overfilled. Builder said "I thought you told me that was a 10 qt pan." Guess they didn't notice the over fill until they drained the dyno oil and re filled. I left the extra 2qts in for storage. Makes me wonder what the true numbers are.