Yanmar oil pressure problem

[Stono]

When coming back to idle after a fast run the oil pressure warning lights, a few revs and it goes out, no more problem, any one come across this before. Yanmar 6BY3 260 hp

 

[B58]

what oil are you using?

 

[earlybird]

If the oil is the correct grade/ level and engine temp. is normal then some suggestions, in no particlar order:-
i) worn crankshaft bearings; ii) worn oil pump; iii) faulty oil pressure relief valve, (assuming there is one); iv) faulty oil pressure switch.

 

[dragoon]

When was the oil and filter last changed? How does the oil level look - too high ( diesel or water contamination) or too low?

 

[B58]

If the oil is the correct grade/ level and engine temp. is normal then some suggestions, in no particlar order:-
i) worn crankshaft bearings; ii) worn oil pump; iii) faulty oil pressure relief valve, (assuming there is one); iv) faulty oil pressure switch.

Most engine manufacturers oil pressure alarm strategy will be between 0.2-0.6 bar dependent on N/A or turbo, I would get an oil pressure measurement taken from the main oil gallery when the engine is hot at low idle, the figure will tell you your engine condition.

I think your problem is based on the condition of the baffle in the sump, allowing oil to uncover the pick-up and aerating the oil in the gallery.