Engine psi leveling

[Beerlust]

Dear Clubsearay,

I have been experiencing uneven engine psi in a 2005 300 sundancer with twin merc 5.0 injected.

How much difference in engine psi is typical in otherwise seemingly perfect running engines.

I apologize for not having exact psi readings however this weekend will provide the opportunity.

As always, thank you in advance for any insight.

 

[hottoddie]

A small difference can be expected. If the readings have changed from before then yo may have a faulty sending unit, gauge or believe it or not oil filter.

 

[Dieseljeff]

10% between all cylinders is the norm. I'm not sure you would want to compare one engine against the other but...10 percent between cylinders on each engine is considered normal.

HTH's

Jeff

 

[IanBat]

What PSI are you asking about?

Engine oil pressure ?

Or

Cylinder Compression,

As so far you have 2 answers one aimed at each above


Sent from my iPad using Tapatalk HD

 

[Beerlust]

What PSI are you asking about?

Engine oil pressure ?

Or

Cylinder Compression,

As so far you have 2 answers one aimed at each above

Thank you for responding. Engine oil pressure is displayed. The difference between engines is around 9-10%.

 

[ZZ13]

That's water pressure that is shown on Smartcraft. It's the cooling water pushed through the engine by the impellers/water pump. On my 300DA I saw around 8-10psi at cruise and about 1.5psi at idle.

 

[Beerlust]

Engine oil pressure is displayed on the analog display. The difference between engines is around 9-10%. Is this normal?

 

[fwebster]

It is a reasonable difference. To determine the cause of the differential, you can swap the oil pressure senders and see if the difference follows the sender. If it does, try replacing them with 2 new senders........if the difference is bothering you.

 

[Beerlust]

It is a reasonable difference. To determine the cause of the differential, you can swap the oil pressure senders and see if the difference follows the sender. If it does, try replacing them with 2 new senders........if the difference is bothering you.

thanks Frank.

 

[Lazy Daze]

FYI, there are now three different "pressures" referenced above. Oil, water and cylinder. No big deal as it usually works it way out. But, to add something to what Frank said about oil pressure - for those that don't have Smartcraft, in addition to the typical "analog" gauge for oil psi, there is a digital readout as well. Sometimes, though, this can be a detriment since folks will focus on exact numbers. Rarely is that needed or even recommended. The better thing is to track "trends" - obvious changes or slowly declining numbers over the season or from one year to the next. That's much more important than a finite number. Case in point - the oil psi spec for your engine is somewhere around 6psi. Different oils, ambient temps, engine temps, filters - they can all cause differences in the exact number.

 

[Beerlust]

FYI, there are now three different "pressures" referenced above. Oil, water and cylinder. No big deal as it usually works it way out. But, to add something to what Frank said about oil pressure - for those that don't have Smartcraft, in addition to the typical "analog" gauge for oil psi, there is a digital readout as well. Sometimes, though, this can be a detriment since folks will focus on exact numbers. Rarely is that needed or even recommended. The better thing is to track "trends" - obvious changes or slowly declining numbers over the season or from one year to the next. That's much more important than a finite number. Case in point - the oil psi spec for your engine is somewhere around 6psi. Different oils, ambient temps, engine temps, filters - they can all cause differences in the exact number.

Very much appreciated.

As i recall the port is reading 7-8% psi and the Starboard is reading 17% psi but that sounds high now. I will check it out this weekend and report back. Also, the starboard side might be burning more fuel.

 

[Lazy Daze]

Very much appreciated.

As i recall the port is reading 7-8% psi and the Starboard is reading 17% psi but that sounds high now. I will check it out this weekend and report back. Also, the starboard side might be burning more fuel.

Regarding engine oil PSI... although both of those numbers are above spec, they are considerably lower than "norm". Norm will usually run around 30 hot and 60 cold - give or take. I suspect you may just be reading the wrong screen or not remembering it correctly. We'll know more this weekend - please verify what screen you are on, as well.