Oily exhaust

[tlkenyon]

Classic R21 with yanmar 30. When I have pulled into the boat lift the past two nights, I have noticed an oily sheen in the water near the stern. Tonight I saw that it is coming from the water discharged with the exhaust. I have never seen this before. I end up with a a rainbow slick 20 feet I diameter or so. The oil level in e engine is ok. There is no oil in the bilge.

Ideas? Is this serious?

Thanks in advance,

TK

 

[abcandjrc]

Just a thought, but has engine performance changed any? You may have an injector that is leaking or way out of calibration. That would be a possible source of unburned fuel in the exhaust. Do you see any similar slick if you just sit idling someplace in calm waters?

 

[tlkenyon]

No change in performance. I have a water temp gage, no change there. Oil pressure OK at about 50 psi. No oily stuff at any other time. I always have a short period of near-WOT before returning to warm things up, but always return slowly to normal temp ( 10 min or so at about 2000 rpm) before hitting the lift. In short, nothing has changed except the oily exhaust. Kinda got me worried.

 

[knotflying]

I doubt it, but by chance is this engine turbo charged?

 

[tlkenyon]

Found the problem. The previous owner installed an oil pressure sending unit on a tee with the OEM unit. The vibration of the engine caused the brass threads entering the engine block to fracture, causing an oil leak. The leak was very small until I started the engine this morning (to take a close look in the daylight)when it cut loose altogether. Ended up with a real mess in the bilge, which was the actual source of the original rainbows. Replaced the missing oil, reconfigured the fittings. Bilge is a mess with a half-inch of oil on top of the water. Gonna put the boat on the lift, pull the plug, and rinse/scrub thoroughly with Dawn into a bucket beneath the boat. Change the oil, etc. Fun.

Amazing how much oil can come out of such a small hole in so little time.

Thanks everybody for the messages...

TK

 

[Brian B]

Found the problem. The previous owner installed an oil pressure sending unit on a tee with the OEM unit. The vibration of the engine caused the brass threads entering the engine block to fracture, causing an oil leak. The leak was very small until I started the engine this morning (to take a close look in the daylight)when it cut loose altogether. Ended up with a real mess in the bilge, which was the actual source of the original rainbows. Replaced the missing oil, reconfigured the fittings. Bilge is a mess with a half-inch of oil on top of the water. Gonna put the boat on the lift, pull the plug, and rinse/scrub thoroughly with Dawn into a bucket beneath the boat. Change the oil, etc. Fun.

Amazing how much oil can come out of such a small hole in so little time.

Thanks everybody for the messages...

TK

Oil absorbent cloth (looks like a diaper) will help with soaking up the oil. West Marine sells them, maybe a local auto part store. I keep about 1/3 of one in the bilge. They absorb oil but not water.

 

[tlkenyon]

Thanks...I will get some. Got a lot of scrubbing to do. What a mess.

 

[knotflying]

You are lucky you were there looking at it when it happened. It does not take long for engine damage to occur with a major loss of oil. Thank God you just have to clean up the oil.

 

[tlkenyon]

Yes, I was lucky. Fortunately, the pressure drop at the OEM sensor caused the alarm to go off, and while I was not looking at it, I am sure that the gage dropped to zero. I am looking t replacing the analog gage with a digital gage. The sensors are wore accurate and physically smaller. Looking at the same option for water temp. Also considering an EGT sensor...all low draw digital.

 

[mspaugy]

You may want to consider a low oil audible pressure alarm if that is feasible?

 

[tlkenyon]

The OEM alarm is certainly audible, but I hate to rely on "idiot lights" or buzzers, as may be the case. A gage can provide warning..... Case in point is my water temp gage. I can back off a little from WOT and not hit the buzzer, and also see when temp has returned to "normal" prior to shutdown.