Low oil pressure

[sebas54]

I have a 1987 gm 4.3l merc alpha 1.

What oil pressure is too low to run at 3900 rpms. I have 45psi for the first 15mins. Then it will drop to 30-35psi.

IS this oil pressure to low to run at high rpms?

I changed the sender last year when it was acting this way, then it would stay at 40-45psi. This year it dropping to 30-35psi. I am going to the store to buy a mechanical gauge. What could cause this?

Thanks

 

[sebas54]

Re: Low oil pressure

Don't know hours but do know that it was installed 3 years ago from a truck.

30weight oil synthetic

 

[Zackman]

Re: Low oil pressure

Oil viscosity will drop as its temperature rises. As the oil viscosity drops so does the oil pressure. This is one reason for the multi-viscosity oils that have become so popular with today's hotter running engines.

I think most marine engine low oil pressure switches are set for 5-6 psi. The amount of oil pressure is more of a concern to ensure adequate flow and yours sounds pretty good. Go enjoy your boat.​

 

[sebas54]

Re: Low oil pressure

Thank you. I am just always worried while out on the water. I do I have sea tow and haven't had to use for 2 years and I want to keep it that way.

 

[Lupus]

Re: Low oil pressure

Hallo,

If reading the specification for the engine it says (at warm stage) that from 2000 RPMs and up you need 40-60 psi. 30 psi at this high rotation sounds low to me - Not sure it will hurt at all but my engine 5.7GSI reads ard. 45-50 psi at ard. 4000 RPM. Better ask your local dealer if you want to be sure. Happy boating!

 

[Fun Times]

Re: Low oil pressure

Don't know hours but do know that it was installed 3 years ago from a truck.

30weight oil synthetic

Just curious what oil filter are you running? Check out this link and read post number 10, I found it intersting You might to
http://www.performanceboats.com/html/forums/showthread.php?t=38440