5.7gs low oil pressure

[Galvez83]

Question for those that might be familiar with low oil pressure. New oil psi gauge reading 20psi. Changed sender and sensor and no change. No noise or weird sound coming from the engine. I changed all new gauges from Faria. Prior to the change it was showing 20psi. New to me boat. Compression 175 to 180 across the board. When i rev the engine it goes to 30 max. What could cause this reading? If the reading is true how could i attempt to bring it up? Any input is appreciated. Also engine hrs are 300. As per the hour gauge.

 

[ESGWheel]

New oil psi gauge reading 20psi. Changed sender and sensor and no change. No noise or weird sound coming from the engine.

At least not yet but it’s coming. That low of a pressure will result in a ruined engine as I am sure you are aware of and concerned about. You need to get a decent mechanical oil pressure gauge and validate the reading. Do that ASAP and do not run the engine otherwise. Post what you find and we’ll go from there as there are a lot of things can cause low oil pressure.

 

[Scott Danforth]

Use a mechanical oil pressure gauge to verify

Only way to fix low oil pressure is pull the motor, inspect all bearings and the oil pump. Then correct what is out of spec

Rule of thumb. 10 psi per 1000 RPM for an SBC

 

[Donald0039]

Use a mechanical oil pressure gauge to verify

Only way to fix low oil pressure is pull the motor, inspect all bearings and the oil pump. Then correct what is out of spec

Rule of thumb. 10 psi per 1000 RPM for an SBC

+ 1. Check with a mechanical gauge.

 

[Galvez83]

As a follow up to this post. I checked with a manual gauge and it tested great. It looks like the sender i had changed was either faulty or innacurate. I purchased another sender and installed. The current reading is 50 to 60 psi at idle.

 

[ESGWheel]

That is good news but, wow, 50 to 60 at idle seems excessively high and more associated with the WOT. Typo?

 

[Galvez83]

Appologies, i meant to say 40-45

 

[Lou C]

Your oil pressure will vary with RPM, oil temperature and the viscosity of the oil you use.
At idle using 25/50 syn blend oil I get 40 psi with cool oil temps and it will drop to 25 psi after running on plane at slow idle where the oil is throughly heated up. Running on plane it will read 55-60 psi. Electric gauges aren’t super accurate but this is a consistent pattern I have observed over many years and different oil viscosities (straight 30, 40, 25/40, 25/50).

40-45 at idle sounds fine. Also listen for an increase in engine noise at slow idle after running on plane, that can be a sign of wear or using oil that’s not high enough viscosity for marine use.