250 Hino no oil pressure

[Kimandrich]

Boat ran for 6 hours and didn’t miss a beat. I start it every two weeks in the slip and warm motors. Today I started them, the starboard motor didn’t show any oil pressure and alarm was sounding. I checked the wires, they are all tight. And both oil pressure gauges go from completely to the left to 0 when key is turned on. Oil level is good and looks good. I ordered oil filter from Napa, it will be here Wednesday. Going to try that. I removed one of the oil sensors and turned over motor with stop button pushed in and the slow stream of oil never increased coming out of the housing. Bought boat about 2 months ago, trying to work the gremlins out. Has anyone ever had something like this happen?

[Nauti_Mike]

I would start by using a mechanical oil pressure gauge to check to see if there is oil pressure or not. You can get one from any auto supply store.

[stanfromhell]

Then use a couple of 6" jumper wires to swap the signal wires from port to starboard. If the problem goes to the other side, your sender is faulty.

[Nauti_Mike]

6"? (inch) no room to work between those engines

[builderdude]

No oil pressure showing at the gauge coupled with the alarm sounding has me thinking it’s possibly more than a sender or low pressure switch issue. Id still verify with a mechanical test gauge as Mike suggested.
something like this.
https://www.amazon.com/gp/aw/d/B0778...?ie=UTF8&psc=1

[Nauti_Mike]

No oil pressure showing at the gauge coupled with the alarm sounding has me thinking it’s possibly more than a sender or low pressure switch issue. Id still verify with a mechanical test gauge as Mike suggested.
something like this.
https://www.amazon.com/gp/aw/d/B0778...?ie=UTF8&psc=1

Yup because if verified the OP is then looking at an oil pump/relief or main bearings. The OP did not mention but with no oil pressure this engine should have been making some noise.

[Jmason]

When did the oil get changed and filter replaced? If it is a drop-in cartridge make sure it is right side up. Up-side down filter could restrict oil flow.

[Don77]

No oil pressure showing at the gauge coupled with the alarm sounding has me thinking it’s possibly more than a sender or low pressure switch issue. Id still verify with a mechanical test gauge as Mike suggested.
something like this.
https://www.amazon.com/gp/aw/d/B0778...?ie=UTF8&psc=1

500 PSI
I am glad none of my engines need a tester with that range, can't imagime any seals standing up to that.
Any auto supply will have a oil pressure gauge that will work and only go to 80 PSI.
Don

[builderdude]

Does transmissions too, 500 for an oil pressure gauge is a bit excessive though🙃🤣

[Kimandrich]

Thanks for all the advice, I replaced oil filter today and bought an oil pressure test kit from Napa, I had a friend turn the key while folding the stop button while I looked at oil pressure gauge. Oil pressure was at 0. I then added oil just in case the previous owner replaced the dipstick and it was wrong..... no luck. I pulled the cap, spring and plunger out on the right side of the filter, it seemed to push back in and move easily. Trying to figure out where to go from here.

[Nauti_Mike]

If you don’t have the manual for this engine get one. Then look to see how to change the oil pump. Also look to see if there is a separate oil pressure release valve. My knowledge on diesels is limited so I’m not sure where the oil pump or relieve are located and how accessible. When my 5.7 lost oil pressure I removed the belt and grabbed the crank pulley and could wiggle it around a little which told me the main bearings were gone.

[Kimandrich]

Had great oil pressure when we moved it after buying it, 6 hours. Then started and warmed up after a couple weeks. Went to start again and no pressure. Thinking bearings are good. Only ran for 5 seconds. I downloaded the service manual and am leaning towards oil pump like you said.... just want to make sure I’m not working myself to death.

[builderdude]

I’m also not a diesel guy but like Mike I believe there should be an oil pressure relief valve in the system. These valves can stick in both the open or closed position, open in your case if that’s actually the issue.

[Kimandrich]

That’s what I’m hoping!, thTs my next step. I see there are 3 different regulator/reliefs

[Average_Joe]

Maybe time to give Earl Summerville a call before all the “maybes” and “what if’s” drive you nuts. He’d probably have it figured out in an hour.

[Pcpete]

Plus one on Earl

[Kimandrich]

Pulled reliefs and found debris in the center one. Put back together and operating as it should. Thanks for the help