2004 Super Sport low oil pressure

A buddy bought a 2004 SS with a PCM ZR6 with about 500 hours. During test drive we hit 48 mph GPS and drove for about 25 minutes at varying speeds. Other than being over-propped and having an awful hole shot and test driving in a thunderstorm, the boat ran ok.

After getting it home it kept going into limp mode apparently due to low oil pressure (supposedly had a mechanic put a gauge on it and it was low at idle. I don’t know how low, but no tappet noises or other signs of bad rod or main bearings.

I’m trying to help and suggested running higher viscosity oil (40 or 15-40), or perhaps (Zach suggested) a replacement oil pump. Obviously if pressure is low there’s a clearance problem on the mains but I’d like to offer him some suggestions before pulling the engine and dropping the crank for a full checkup.

Is there a possibility of buying a higher volume/higher pressure oil pump? I know the old 1969 Z-28 with the 302 had a higher volume pump. Other than that piece of trivia I know little to nothing to help him.

POWER REDUCTION MODE The ECM monitors engine oil pressure and engine coolant temperature whenever the engine is running. If either one of these inputs indicate an abnormal reading, the system will go into “Power Reduction” mode, followed by the illumination of an indicator lamp and/or sounding of the warning buzzer (if equipped). This is a feature that will help protect the engine during an overtemp or low oil pressure condition. When in “Power Reduction” mode, the ECM will allow normal engine performance up to 2500 RPM. Above 2500 RPM, the ECM allows fuel delivery through only half of the fuel injectors. Once the RPM is brought down below 1200 RPM, normal engine operation is restored until the RPM exceeds 2500 RPM. The feature allows maneuverability of the boat while removing the possibility of high engine speed operation until the problem is corrected. NOTICE: If it is not possible to safely shut off the engine, return the engine to idle speed. Once returned to idle, the ECM will allow the engine to operate normally below 2500 RPM

huh.

Before I started tearing into the engine, I'd get some better information about oil pressure at various rpm's

I guess only you and the friend and the mechanic might know the numbers, your first post said low at idle, no mention of what it was at any other speeds.

Assuming the long shot of higher viscosity oil fails as it probably will.

Let's see, the boat has an 04 engine, the above is about an 08 engine.

My wife has a BMW X5 with the V8, there is a nice engine oil cooler.  Like your Volvo they used Orings to seal the cooler lines.  German law says they must use Recycled product, these Orings go out around 100,000 miles and create a high pressure oil leak.   Of course they are mounted on the side of the engine between the motor mount and the frame, below the exhaust and above the front differential.  BMW says 17 hours to change these $7 Orings.   I did hers in the garage, did all other service at the same time.  I never want to wrench on it again.  Nice car but that is ridiculous.