Yanmar 4LHA STP oil pressure

[Yannis]

Up until yesterday, whenever I started my engines, after 2-3 seconds the oil pressure would jump to reading 4. At neutral idle.
Since yesterday, my port engine shows oil pressure 2 at neutral idle, also at forward idle, and it takes some revs like 1500 to go to normal 4.
Am I to remove that engine and drop it in the water or can this be fixed?
I’m in no way close to being a mechanic and all this is chinese to me...

[mike ohlstein]

I think you're ok with that. If you have good pressure at 1500 rpm, and just about any pressure at 800 rpm, you're fine. Especially when the oil is warm.

[Carl]

Did you check your oil level?
When was your last oil change?
Use the same brand and weight as always, same filter?
Engine running hotter than usual?

Did you change your low idle speed?

Can you verify your gauges with a mechanical or swap leads from the other motor?


On my gas motors if I used two brands in particular they did not hold up very long. Other oils 50 hours I'd start to notice a drip, these two I speak of half that amount and they would start to thin out leaking past the rear main seal. What a pain putting diapers down and sucking up oil. My pressure was always up there...but I had high output pumps.
Anyway, its something to look for.

[Yannis]

Thanks Mike. It sounds like you said.

Carl,

Oil level ok, change oil every year, temps normal at 70-75, all filters ok, no oil in the bilge.

However, I suspect some humidity in the port meter. I will not start switching cables between motors, I’ll live with that, I’ll spray it tomorrow and see if there is any improvement.

I heard about a valve or something on the engine somewhere that could be the culprit ...I’ll do the spray job to eliminate humidity and will come back.

PS: I did some hose rinse ON the gauges a few days back, perhaps that’s the thing. I had to get rid of African dust somehow!
I was holding my ouzo glass on the other hand...

[Carl]

PS: I did some hose rinse ON the gauges a few days back, perhaps that’s the thing. I had to get rid of African dust somehow!
I was holding my ouzo glass on the other hand...

well of course you were holding it, you cannot put that down.

[Yannis]

Ha ha ! Indeed for fear of stumbling on it later!

That whole instrument panel has given me a few problems over time. I should start thinking of redoing it somehow. Also to reposition the meters somewhere higher so that they are clearly visible and not behind the wheel...I tilt my head left and right to read them. Very stupid arrangement.

[Carl]

Boats are built on compromise.



At least the boat I can afford...lol


Now I am thinking K-mart blue light special....SORRY BOB!


Yannis I often wonder how some items are built. People lay it out,but never actually use

[Tony Meola]

Yannis

On the Cummins at idle my guage shows around 10 lbs, when hot the Starboard engine stays at 10, the Port drops to 5 at idle. Once I push it up I jumps right up to normal.

[CamB25]

Boats are built on compromise.



At least the boat I can afford...lol


Now I am thinking K-mart blue light special....SORRY BOB!


Yannis I often wonder how some items are built. People lay it out,but never actually use

Years ago I saw great sign hanging in a project manager's office - "Sooner Or Later You Have To Shoot The Engineer and Build The Project" This could be a corollary to the "better is the enemy of good" truism. I, of course, ignored all of this, but I still have some "should-a-done this differently" items on the boat.

[Rawleigh]

A temporary jumper wire from the sender on the problem engine to the lead to the other gauge will tell you if it is the instrument or the sender/engine. I always put a threaded nipple and tee on the oil port so that I can attach a small mechanical gauge on one side and the sender on the other. I like the backup and comfort of looking at a mechanical gauge if I have any question about oil pressure!

[Yannis]

Rawleigh, I thought you were a lawyer, lol!!!

[Rawleigh]

Its my alter ego!!