Mercruiser 5.7 loss of power and oil pressure
 

Hey all,

I'm a little lost so I'm going to get right down to the information I do know.

Taking the boat out the last time this season it started to bog down badly when running about 3,500 rpms with me and one other passenger. I pushed the throttle to WOT and it began to bog worse, it began to lose oil pressure so I cut the throttle back and shut the engine off, found oil in the engine bay and the engine about 3/4 of a quart low on oil. I don't believe the oil leak is too severe, after being towed back to my well I topped off the oil it starts, runs and free revs fine and does not over heat. It only seems to bog and loose pressure under load.

I need some advise on where to start, I would consider myself fairly mechanically savvy, I will be checking the engine compression and root causing the oil leak within the next week or so!

SOS lol


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Re: Mercruiser 5.7 loss of power and oil pressure
 

I'd start at the sending unit for the gauge and the one for the alarm Dan.
Could have possibly blown a sending unit , letting oil escape.
Could you tell if the oil came from the front or the rear of the engine? Right or left side?
The bogging is possibly due to the lack of pressure at the alarm/gauge sending unit , causing a shutdown of the engine.
Check around intake at the heads and front and back of engine. If you lost a gasket there it could cause bogging also , though unlikely.
Do you hear valvetrain "rattle"?

Just a few things that come to mind off hand.

Let us know what you find.:wink_thumbup: