Low oil pressure

[Mickey D]

I have an 89 Merc 454 Mag with 365 HP. I have been getting a low oil pressure warning light that flickers when the motor is warm and I am idling or running with no wake. The pressure gauge needle bounces around a bit so I dont know if it is a problem with the gauge itself or a sending unit. It seems to respond well at faster speeds. Any input would be appreciated.
Thanks
Mike

 

[Bt Doctur]

Re: Low oil pressure

What kind and weight of oil your using
What the engine temp is?

 

[Mickey D]

Re: Low oil pressure

Just had the oil changed and told them I wanted SAE 40. Of course I didnt watch them fill it but I would hope that is what they used. Boat runs cool. I think it was 120 or under. When I increase the RPS the pressure goes up and stays there until I drop it back down. The boat only has 360 hrs on it. Im hoping that it is something with the gauge or sending unit. Its almost like the needle is loose if that makes any sense. Obviously I'm knew at this.

 

[billbayliner]

Re: Low oil pressure

I doubt this is the issue to your specific problem but wanted to throw this in as it some how relates to low oil pressure.

Recently had an issue with the oil pressure, at idle, on an engine not high enough to prove and allow electric fuel pump to activate.

Oil viscosity, as described above, was thought to be an issue. Pulled the dip stick and the oil reaked of gasoline. Gas in the oil had thin it out and in-turn could not prove oil pressure.

Changed oil to 40W and all issues solved.

Bill

 

[wca_tim]

Re: Low oil pressure

beg, borrow, buy, steal a mechanical oil pressure gauge and hook it up to see what the pressure really is...

 

[JustJason]

Re: Low oil pressure

As wca tim says... you really need to double check it with a mechanical gauge.
That being said... make sure your not over filled. As aerrated oil with do what your experienceing.