Oil light won't go completely out + tone

[rblevens]

My Yanmar oil idiot light just won't completely go out... (say 98% out) and the tone almost can't be heard... normal or not?
Low RPMs- fresh oil and filter- yanmar 3qm30h.
(Trying to commission a used engine I bought)
Comments?

 

[kloudie1]

Oil pressure switches do go bad.. and they are pretty cheap.. also check the sender wire from the switch to see if it is shorting on the block or something else.. next place to look is for debris in the oil pressure control.. A small bit of stuff can hold the pressure control valve partially open and give low oil pressure

 

[rblevens]

All good stuff... thanks!

 

[rblevens]

Where is oil sender located on the engine... I assume down by the oil filter... ?
3qm30h

 

[Johnb]

You might find the attached wiring diagram handy - it shows the wire colors.

This diagram is also in the service manual which is available as a PDF.

 

[rardiH36]

Photoed these from my on board Seloc manual. Location of the oil pressure sender the 3QM's. And troubleshooting tips.

 

[Bill Roosa]

switches for idiot lights don't have a partially off feature. Soooo it is not the oil pressure switch. If you look at the wiring diagram you will notice a diode in each idiot light circuit. Those do go partially bad and pass current

 

[rblevens]

Thanks a bunch!

 

[Benny17441]

You may also want to check for a short circuit in the wiring harness from engine to control panel. the wiring harness is routed around fiberglass sharp edges and after many years of hull flexing the insulation can and will chaff causing shorts and problems with the buzzer and warning lamps. A visual inspection of the harness specially where it turns corners will reveal any spot with chaffed wire insulation.

 

[bawlmer]

Same thing happened to me. I do not have a oil light but the buzzer chirped like crickets. I traced it to an intermittent connection at the OP sensor connection. When the engine ran it was vibrating just enough to cause chirping. I tightened it and it stopped for a while. eventually I got used to it. In my case it did not affect the operation of the OP warning system so I let it be. YMMV.

 

[rblevens]

You know, if I put it at a certain RPM it vibrates, too... not noticed the issue before that... weird.
Take a peek at it Tuesday...

 

[Jim Legere]

Our 3 cylinder Yanmars do get the 'shakes' at certain RPMs - my 3QM30 is rough in the 1700 - 1900 range and smooths out above 2000 RPM. Also, my charge light glows faintly with the key turned to "OFF".

 

[Coastal Nomad]

Had the same light and buzzer problems. The control panel for my 1GM is located in the cockpit and exposed to the weather. Pulled it apart and found quite a bit of corrosion, poor electrical connections (bad lugging and solder joints....solder joints?) Cleaned it all up and did it right (I'm a marine electrician of a retired US Navy variety) and voila! No more problems! I did check the wiring and sensors while I was at it as well. No probs on the engine side.