Oil pressure Yanmar 4JH5E

[01kiwijohn]

It should be pretty easy. Look along the side of the engine, where the oil filter is, and there should be the oil pressure sensor, with its' electrical connector. unscrew the sensor and thread in the gauge. There usually is another plug, or two, indicating where there are access points into the main oil gallery; those will do the same job for you.

[Compass790]

Pretty much they got u covered here AFAIK, can only add I screwed 1/8" NPT tee into our Yanmars sender hole to install a gauge in parallel with alarm with no tapping & thread tape on it or loctite ( has been out a couple of times ) with no leaks. Suspect your oil pressure alarm is working as oil thins as it gets hotter therefore resistance to flow ( pressure ) drops but as A64pilot says ya wont know until you check. Any 1/2 decent mechanic should have an oil pressure gauge but maybe not in The Marqesas. Another cruiser should be able to lend u theirs temporarily if easy to remove gauge. Also try increasing idle slightly.

[Compass790]

Whoops! just realized that my post could be confusing. I did use either thread tape or Loctite on the tee threads.

[jjorio]

A big thanks everyone.
I'm trying to locate a pressure gauge now to check all this properly.
I'll set the rpm a bit higher, when I come back to the boat in a couple of hours.
cheers

[Compass790]

Originally Posted by jjorio

A big thanks everyone.
I'm trying to locate a pressure gauge now to check all this properly.
I'll set the rpm a bit higher, when I come back to the boat in a couple of hours.
cheers

Let us know what you find out please. good luck finding a gauge

[jjorio]

Didn't find the gauge for the moment, but I'm looking at the sensor that is installed on the oil gallery, and I wonder if it is the actually gauge sensor WITHOUT the pressure reader on the panel at the helm.
In that case I can fit a gauge just by connecting it to the sensor already in place.
Is this possible, or am I dreaming ? I'll attach a pic now.
Makes finding the gauge much easier ...

Also, for this engine idle rpm is between 775 and 825rpm, the rpm was set on 775. I changed it to just below 825rpm.
The gears engage smoothly.
I'm testing now if my oil pressure alarm fires again.
Pic coming

[jjorio]

Here is the sensor picture (finger pointing ), that is installed on the engine.
The wire that connects at the end of the sensor goes to the oil pressure alarm on the control panel.
Any clue ?

[jjorio]

Dear everyone ,
I'm ashamed, and beg your indulgence.
I'm facing my mistake publicly :
It was not the oil alarm, but the temperature ...
In the rush to shut down the engine, I got mistaken with my reading.

Sorry ...

As I still have a problem, but different, I'll create a new thread

PS : I wonder if the overheating could also cause the oil alarm to fire as high temperature fluidifies the oil too much ...

[Wotname]

Originally Posted by jjorio

Didn't find the gauge for the moment, but I'm looking at the sensor that is installed on the oil gallery, and I wonder if it is the actually gauge sensor WITHOUT the pressure reader on the panel at the helm.
...................

Originally Posted by jjorio

Here is the sensor picture (finger pointing ), that is installed on the engine.
The wire that connects at the end of the sensor goes to the oil pressure alarm on the control panel.
Any clue ?

That sensor is your low oil pressure switch. The switch operates when you have low oil pressure.

A pressure gauge needs a different type of sensor but connected into the oil gallery at the same point (or close to it).

Now to sort out the temperature problem .

[Compass790]

Originally Posted by jjorio

Dear everyone ,
I'm ashamed, and beg your indulgence.
I'm facing my mistake publicly :
It was not the oil alarm, but the temperature ...
In the rush to shut down the engine, I got mistaken with my reading.

Sorry ...

As I still have a problem, but different, I'll create a new thread

PS : I wonder if the overheating could also cause the oil alarm to fire as high temperature fluidifies the oil too much ...

No worries mate, have to confess I've done the same meself

[Wotname]

Although the OP no longer needs to fit an oil pressure sensor to his Yanmar, for others reading, here is one way to fit a NPT threaded device to a BSP housing without re-tapping. Note this is not best practice but it does work and sometimes cruisers just have to make do with what is at hand, especially in foreign ports.

The premise that a male BSP thread will screw into a female NPT thread but not vice versa ant you will need a thread sealant using this method.

Let the pictures tell the story.

[magnificat]

Don’t run in idle. Just kidding. Check the actual pressure with a gauge to see what is happening.

[jjorio]

THat's what I did at first place as I had to move the boat ...

Anyway I moved the thread here :
Coolant temperature at idle rpm on Yanmar 4JH5E - Page 3 - Cruisers & Sailing Forums

Cheers

[Benny737]

Originally Posted by a64pilot

Install a gauge and see what pressure really is, you may or may not have a problem, until you determine actual pressure, your just guessing

What would be the normal oil pressure for this engine?

[Tin Tin]

I would unscrew the pressure switch, examine it and the housing it is screwed in to. Clean the wire contacts/plug. Clean the switch. I would spray it all with WD40 (but that's just me) Screw it back in with some thread seal. If it still plays up at least you have eliminated the obvious. If you have a friendly cruiser in a Lagoon with Yanmars they might let you transpose one of their pressure switches to see if that is the problem by elimination.