Oil in bilge Yanmar 2011 150 hp,

[nzfisher]

So the best thing about owning a Ranger is right here- expert knowledge base of users ready to share their combined knowledge and history. That being said I was witness to some bad news today- not a heart attack but close in the world of boat ownership but truly a first world problem. Luckily I was starting the boat on the hard to prep for Poets cove trip which now seems dubious. Big sigh here. Started the boat and it started right up-probably a year since it was last run. Everything looked good but then I noticed a lot of oil in the bilge. Given I just cleaned it last night, ( had more oil than usual then), it should not have so much oil as it was pumping out now. A lot of oil, perhaps half a quart in the three to four minutes of run time before I shut it off. So I put it out there for probable causes so I can benefit from other’s experience. The boat has about 1100 hours, 2011 Yanmar 150 power plant. I vaguely remember someone in the past talking about an little known oil plug near bottom of engine that hod come loose. I am hoping this is the culprit. There is no sign of oil in the coolant system and the engine started right up and rain smoothly so cracked block seems unlikely. The engine has been carefully maintained and rarely run over 3000 rpm throughout its life. I am original owner. Any help would be appreciated. As a footnote the boat has started to smell of chemicals for about a year so it seems likely that a plug started to slowly pass oil. If someone knows where this plug is on block that would be a good place for me to start or other probable causes would be great.

Thanks
Swims with Tunakl

 

[Bruce Moore]

Bummer. Did you check with the factory? Andrew, Kenny, and Tim have the most institutional knowledge of the classics.

Good luck.


Bruce

 

[scross]

We have the 2009 Yanmar 4BY2-150. There was a Yanmar service bulletin on the oil hose in May 2012 that may or may not include your engine.
viewtopic.php?f=7&t=2682

Our boat had been “fixed” when we bought it in 2015 but it was a bad repair. That mechanic stripped the threads where the hose goes into the block during the hose replacement. At 700 hours on the engine we started seeing a lot of oil in the bilge just as you report. Not a catastrophic oil leak but still a pretty serious leak from the front of the engine into the bilge. Pulled the breakers on the bilge pumps. Feed the engine a quart of oil an hour and limped back at low RPM to Bellingham from Ganges BC keeping an eye on the oil pressure the whole trip.
Trailered the boat to Everett for repairs. Took two tries at a boat $ unit each to get everything repaired properly.
I’d check this hose per the service bulletin I referenced above as one possible explanation for your leak.

 

[knotflying]

Yes, there is an oil line that goes from the oil pressure sensor down to a banjo fitting that was originally a solid line with a rubber hose at top and at bottom and it would fail from vibration. The new one is all rubber with a braided sleeve protector. If you have a metal tube then that is my first line of attack. The second could be the bottom oil plug or a rust hole in oil pan, bad gasket, oil dip stick line rusted out etc. Remember that there are two oil dip stick lines, one port and one starboard.
If the oil sensor line needs replacing it was paid for by Yanmar, but at the late date, who knows. If it has to be replaced you need long arms, a mirror and a piece of thread to temporarily hold all the washers and fittings together before connecting ang tightening things up at the banjo fitting.

 

[BB marine]

I would first suspect this
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If the oil leak is when the engine is running it has to do with either a oil pressure line leak or a lower end oil leak like a dip tube or pan leak. The dip tube or pan leak would only be significant if running at high speed when crankcase pressures are greater. The fact that you started it on the hard I would not think crank case pressures would be present. A leak of 1/2 qt in 4 to five minutes suggest a fractured line or a plug or fitting leaking under pressure. A leak like this should be easy to find if the bilge was once again cleaned thoroughly and oil absorbent pads placed through out the bilge. Start the engine for 20 to 30 seconds and then shut it down. No look for signs of the oil leak.

Areas to look for. oil pressure sensors, oil filter housing, oil filter cap, the service bulletin oil line. I also believe Yanmar has an additional oil pressure sending port on the block. This is for a oil pressure alarm when a analog gauge is used. One port for pressure one for alarm. This is not used when the electronic gauge package is used. This plug may have started to leak. Just a few guesses. Good luck!

 

[nzfisher]

Thanks everyone for your thoughtful and valuable information. I had forgotten about the little oil line fix from long ago. At the time, We could not find a Yanmar mechanic who would touch it but found someone in Newport OR that let us use his tools if we did it ourselves. That will be the first place to look although it will still be nearly impossible to get my hands in there…As usual really appreciate the time you folks have given me to help sort out this issue. Taking a little break for mental clarity and will be back at “the fix” this afternoon.

Thanks again,
Swims with Tuna