no oil light

[jrp544]

hi, I have a 2000 evinrude branded Suzuki 50 hp 4 stroke. the 'no oil' light is on. the oil is clean and full, I checked oil pressure with a manual gauge, = 50-55 psi. I changed oil pressure switch, light went out for 2-3 secs then back on. engine runs well, idles well, pulls well, no rev limits in the water. engine will surge at 3k rpm in neutral with flush ears on. anyone have any ideas for me? any info or advice is greatly appreciated. thanks, jp