454 hot idle problem and oil pressure drop and alarmhelp

"Hello To all, I have a 97 7.4

"Hello To all, I have a 97 7.4 merc, it had starvation issues at top end, had carb rebuilt proffesionally,(was bench tested and said needed no ajustment) bolted it on and she started great after a little priming, no idle issues cold..went out on maiden voyage to test idled through channel and pulled hard on wot, no more starvation. comming back to dock, I brought it to idle to plop into reverse and she died. the oil pressure dropped to 10 and the alarm sounded, engine cut out. would not just key start, had to pump and started up (40psi at this point giving 1.2 throttle) then put it to idle and alarm rang again and died (10psi). oil is clear and at full level, while under throttle I have full pressure and no issues, doesnt heatup but at hot idle, pressure drops and stalls-protection cutoff I believe. sender seems to work well at wot and cold, could it be the pump?clogged filter? clogged remote oil passageway?...help please, have sold the boat to upgrade and need her to run right for new owner."

""was bench tested and sai

""was bench tested and said needed no ajustment"

DON'T PANIC!

You'll still need to set the correct hot idle RPM, probably 650 RPMs in gear.

"doesnt heatup but at hot idle"

Sounds like the strainer is plugged or it needs a new impeller in the seawater pump. Hot oil will thin out and cause a drop in oil pressure at low RPM.

What weight oil? Needs to be at least 15W40 Delvac or Shell Rotella, Mercruiser 25W40 or a 15W50 Synthetic. Mercruiser 25W40 preferred for low end oil pressure."