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  Topic Review (Newest First)
06-06-2006 08:58 PM
Irwin32 I am not sure how to tell the difference between diesel and oil when viewed in the bilge and would like to know the difference for future reference.

Know that it takes very little diesel/oil to leave a sheen in your bilge. A few drops will do it.

Probably the only way to isolate the probem is to eliminate each potential source and then observe. Use a rag and wipe it over all areas of your engine. Leaks will migrate to the lowest point so just because you find one at a low spot it does not mean it comes from nearby. On an old boat, oil and fuel may have accumulated all over the engine from oil changes and fuel filter changes. You really need to clean the engine and the adjacent area before you will locate the problem.

Why not pressure wash? A diesel should not be effected. I am not 100% about this so check with a mechanic first.
06-04-2006 11:20 PM
jared Oil and fuel would look different in the bilge. Oil can leak from your transmission, or the engine main seals (front or rear) and be hard to trace. One thing that can help is to put a "diaper", an oilzorb pad, under the engine so any drips or leaks get caught before they run further. To find the leak you'll need to start by cleaning the engine and engine bay. Then place a fresh liner under the engine.
At that point you can spray talcum powder on the engine (it won't hurt anything) and after you run the engine for a while, look it over to see if there is anyplace that there are oil stains running through the talc and dripping under the engine. If you still can't see anything, you can put a UV tracer dye in the oil, run the engine a couple of hours, and use a black light (same kind sold for tracing AC leaks but any strong black light would work) to see where the glowing traces from the dye and oil are.

Residue under the tank could be fuel...but after 30 years it is time to pull and check the tank. It might be a monel tank--top quality and very expensive. Even aluminum can last longer than that without problems, but if it has pinholed, those can also be welded (after the tank is emptied and cleaned).

On a thirty year old boat? Odds are everything leaks.
06-04-2006 11:16 PM
Old stuff leaks...

Motor oil and diesel should be able to tell them apart in the bilge. Anything or thing(s) can leak and it's hard to tell from here. My favorite method is a roll of paper towels and wipe things down clean and then go back a little later and look for fresh drip/puddle. Also, Lay some clean towels down in places you can't reach and then after a bit of a wait pull them out and check for stains.

Good Luck!
06-04-2006 10:07 PM
Tequiza Terri
oil in bilge

I have a 1976 Morgan 28OI. I have noticed that she has oil in the bilge water. I have used sox and I do have a BilgeKleen filtration system. But I am perplexed as to the origin of the oil???? Can an old Yanmar really throw that much oil in the bilge after an hou of use? Can oil leak into the bilge from any other source??? How do I isolate the cause of oil intrusion into the bilge. I have visually inspected the area beneath the engine and I cannot see any visible dripping from the engine while she is running???

She has been sitting a year with no use of the engine and her bilge has been pretty level and free of oil. I recently installed a new starter motor on my Yanmar SVE12 (yes I know it is a real dog!) Once we had her up and running with the shaft turning she did show a leak at the stuffing I expected she would.

I do need to repack the stuffing box and I plan to use the moldable dripless packing. BUT before I can get to the stuffing box I need to remove the old fuel tank. I have suspected that the 30 yr old aluminum fuel tank leaks. The engine compartment is pretty dirty and from what I can see there is a pinkish residue beneath the tank= diesel! Could a slow diesel fuel leak account for the oily residue??

I am replacing and relocating the 30 yr old aluminum fuel tank with a new Tempo tank. Thus fixing the fuel leak and providing easy access to the stuffing box and other key engine components. I am also installing an AlgaeX in line filter.

After I install the new tank I plan to haul her out to inspect the hull, thru hull fittings, keel, cutlass and prop and apply bottom paint. While she is hauled out I am going to clean and paint the bilge and engine compartment. (I wish I could pressure wash the engine compartment! It has 30 years of dirt and residue. But that much moisture and water near the engine is not practical.) Next I will repack the stuffing box and make necessary repairs. Finally, I plan to install Sounddown so that I can hear myself think! She will look better than new when I am done!

Am I missing something obvious? She is built like a tank. I am hoping the Morgan encapsulated keel is OK. Any suggestions on how I can isolate and control the oily bilge???


Terri Ivins
'76 morgan OI 28

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