Dropping oil pressure at idle

[Capta1n]

Dropping oil pressure at idle
Really appreciate any help or ideas.

Motor is a 2002 Mercruiser Black Scorpion 6.2L - a couple of weeks ago I was getting a low oil pressure alarm, I checked the oil level and it was just over full, the alarm would go away with revs, I changed out the sender and the PCV valve and that solved the problem or so I thought until today, Once the engine reached normal temp at idle no pressure with revs 60psi ish, I checked the level again and it was the same just slightly over full but I did notice the oil was very hot.

Other info
oil was changed last April, Quicksilver SAE 25W-40
the level was checked on the water with boat and ballast empty
Engine temp was normal.
Battery charging 13.5V
Probably not be connected but rev counter was a little erratic also. running at 3000 rpm and occasionally it would flick to 4000 and back again.
Video is for sound if it's any help

Any ideas on what to check or is it drag it to the dealer

[chpthril]

April as in 2 months ago or April 2020? Does the oil smell like a hint of fuel? I agree with Gumby, rent a manual gauge and put it in place of the sender and run it under the same conditions. Even better, make a tree and run the manual gauge with your electric sender together and compare in real time.

[Capta1n]

To answer your questions gumby & chpthril, I checked my records and the oil and filter were last changed May 2020 and I didn't smell any fuel from the dipstick.
I have a test gauge and new oil filter coming tomorrow, As you both suggested I will test the pressure with a gauge before I change anything to get a base reading and then do an oil change to see if that makes any difference.

Thanks for the advice.

[boatwakes]

We had a customer with the same issue several years ago and it turned out to be a faulty oil filter bypass. If indeed you find oil pressure low (the switches are set to 7psi) STOP USING THE BOAT and then replace this first and see if the problem resolves.

https://www.amazon.com/Allstar-ALL92...70106080&psc=1

[Capta1n]

Update - ordered the part boatwakes suggested in case I need it, it will be here today, Oil pressure was good until engine reached temp then dropped to 15psi at idle, 45psi at 2000 rpm on the test gauge.
pulled the filter and I may be mistaken but it appeared to be under pressure because as soon as I cracked the seal a fair amount of oil flooded out and that was after I had half pumped the sump. the filter was still full to the top when I actually removed it.
any thoughts on that?

[chpthril]

Normal for oil to be on top of the filter, even when the ban is drained.

[Capta1n]

Update - New oil filter bypass, filter, and oil (Quicksilver SAE 25W-40 as per the manual)
On startup 45psi as idle and 55psi at 2000 rpm
At running temp, 22psi at idle and 45psi at 2000 rpm
Are these numbers OK or do I really have a problem,
Would an oil additive help (if you read the label they are like magic in a bottle) Yeah right

[boatwakes]

Those are good normal readings.

[Capta1n]

Ok great - Thanks all for the help and advice.
It's great to get answers from knowledgeable members and getting back out on the water quickly rather than the boat being at the shop.

Thanks again.

[okiepilgrim]

Ok great - Thanks all for the help and advice.
It's great to get answers from knowledgeable members and getting back out on the water quickly rather than the boat being at the shop.

Thanks again.

I'll second that! This site and the folks that frequent it have 100% been the difference between my family being on the water or not.

[Meridianbigblue]

Hi Capta1n

I have exactly the same problem with my engine (Mercruiser Black Scorpion ski 6.2l) except mine is a 2004.

Is the problem still solved for your engine? Can you tell me what parts you buy and what type of filter? Thanks for your help!

[Capta1n]

Sorry for a late response, i just saw this,
Mine was not resolved and about a month after this posting it detonated at about 3500 rpm, had to get a total rebuild.

My guess is the damage was already done before i noticed the issue.