oil pressure light beeping while engine running? yanmar 3JH4E.

Nov 4, 2012
34
C&C 41 Mattapoisett
Today while starting the engine I heard a small bang sound and it didn't start only after a third attempt ( bogging) it started. On my way back I started the engine again and the oil pressure light stayed on while beeping. I checked the oil level and it was full…..
 
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Likes: Timm R Oday25
Sep 25, 2008
7,236
Alden 50 Sarasota, Florida
Could be bad pump, could be low oil level, could be obstruction, could be corroded connection on sensor or warning buzzer/light., could be other stuff. Or it could be nothing. The real question is whether or not you prefer guessing over a potentially engine destroying issue.
Listen to Justin
 
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Likes: Justin_NSA
Nov 6, 2006
9,984
Hunter 34 Mandeville Louisiana
Next step would be to put a pressure gauge where the pressure switch is and read the real oil pressure. The switches do go bad but until you know what the pressure is, you'd be risking catastrophic engine damage if you continue to operate it.
Some other "Could be's" ;a collapsed oil filter, a debris in the oil pressure relief valve... contaminated engine oil...
 
Oct 26, 2010
2,009
Hunter 40.5 Beaufort, SC
(Rickover trained) Believe your indications (until "proven" otherwise.) The oil pressure light (idiot light) and "buzzer" are most likely operated from the same sensor on the Yanmar and alarm at only a few psi (about 2 to 4 psi) if it is working correctly. If the light and the buzzer or sensed by two separate sensors, then you have TWO indications of low pressure, not one. A few more questions.

"I heard a small bang" does not sound encouraging but could be nothing. The first time you started for the day (after the bang) did the oil pressure light and buzzer come on and stay on or was it only after you started it "on the way back."

How long did you run it with the light/buzzer sounding. It is called an "idiot light" for a reason. (Don't be offended, it is what I grew up calling it as most of us probably did too.) If you don't have an independent oil pressure gauge you would be well served to immediately shut down the engine when the light comes on unless you "know" it is a false alarm. Otherwise you are rolling the dice on causing major damage to you Yanmar. You can either sail back to your location and drop an anchor nearby your final destination and try to call a tow service (you do have a tow service I hope?) or if you can't sail back drop the anchor if the depth is appropriate, crack an adult beverage and call for a tow.

Long winded confirmation of what Justin and Don have said but It is not "nothing." Something is wrong. That wrong thing might be actual low pressure, which at the psi level of the idiot light, could be catastrophic or it might be and indicator problem, but it is something. If it were my boat, I'd troubleshoot it before I ran it again. I'm not one for playing a "game of craps" with my engine.
 
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Likes: LloydB
Oct 26, 2010
2,009
Hunter 40.5 Beaufort, SC
Next step would be to put a pressure gauge where the pressure switch is and read the real oil pressure.
Keep in mind, on a Yanmar, which use BSPT (British Standard Pipe Thread) but most gauges you buy here in the US will be NPT and you will need a converter to install the gauge. You might might get away with screwing the male NPT fitting on the gauge a few threads into the BSPT female on the Yanmar but it will not be a good connection, as the mating surfaces do not match. That would only be a temporary solution to check the pressure as part of troubleshooting. BE VERY CAREFUL if you do not use a BSPT male to NPT female converter as you risk damaging the threads in the Yanmar and then you are in for more "repairs."