curious diesel leak

HerbertFriedman

Member III
Normally the bilge on my '87 E34 is bone dry during the summer here is the SF bay area. The dripless prop shaft coupling works great. Recently after topping off my diesel tank (typically done every ~15 hours run time) I noticed what appears to be a mixture of oil or sludge and diesel in the aft portions of the bilge, maybe 1-2 cups. Pouring this mixture in a glass of water shows it first beads up, then breaks up and floats to the top. Could be from the engine, fill tube or the diesel tank but definitely not water.

Cleaned out the bilge and over the next few days, the liquid amount decreased and finally stopped. Ran the engine for 30 mins in gear at 1500 rpm with white absorbent pads under the engine, no leak there. Oil filter, fuel filters, pan gasket all dry. Filled the tank again, maybe 1/2 gal, and next day some liquid appeared in the bilge, much less, maybe 1/2 cup. Again liquid decreased over next few days.

I could feel no wetness around whatever I could get my hand on the fill tube. All the hose connections to the tank were tight. Maybe 1/2 turn on the hose clamp at the fill port. Could get my hand to most of the front bottom on the tank, no wetness there. I am stumped, short of emptying the tank (it is now full, 20 gal) and pulling the tank, any ideas out there??
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
That has happened to me when topping off, so I no longer top off. It puts pressure on the seal of the fuel gauge port, as well as filling the intake hose and vent. The port then dribbles fuel into the bilge until the tank level decreases.

So, eyeball the fuel gauge port and check its seal. I had to go up a size in the five sheet metal screws and change gasket for a tight seal. The port is only "underwater" when tank is brimming full.
 

HerbertFriedman

Member III
Christian, I did have the "admiral" (wife) view the tank with the hatch cover off, when I topped off the tank for the second time and she reported "no leaks" but she might have missed it. With your experience in mind, I will try this over again. Thanks for info.
 

Shankara

Member II
The last time I filled my diesel tank all the way to the top, and then there was a strong wind afterward - bouncing the boat around, there was some leaking - coming out of the seal at the top of the tank where the fuel gauge float drops in.

I thought for sure I had a fuel leak because I was seeing it in my bilge like you were. Not the case.
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
On the 32-3, the fuel gauge sender port is located about 1.5" below the top of the tank. When the tank is topped off, this seal is "underwater" and under pressure. Even if it's a good gasket and seal, it will seep diesel.20220902_211241~2.jpg
 

HerbertFriedman

Member III
Ken, thanks for the photo and info. I think my fuel gauge is different from yours. Mine just has an analog gauge on its face so I think there is no sender just some sort of float connected to a needle. But I suspect this gauge is the problem. I will take a photo and post it tomorrow.
 

Teranodon

Member III
I had a pinhole leak in my tank. In the welded seam, invisible to the eye. Best way to locate it was by applying some folded toilet paper to various places on the tank. The pink dye from the untaxed fuel showed up clearly. I assume this method would work on other parts of the system.
 

HerbertFriedman

Member III
Was the leak in the top or bottom of the tank, and how did you repair the weld? If the pinhole was in one of the bottom welds, the leak would always be present, not just after topping of the tank. I did spread white absorbent pads around most of the tank, but saw no red diesel, but I will keep looking.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
If you are 'lucky', there might be a tiny nick or split in the fuel return hose where it it clamped to the fitting near the tank top. I just found and fixed a minor seepage from that particular hose. I was fortunate in that the end of the hose was nicked a bit where it had been clamped the last time the tank was removed and reinstalled. There was just enough slack in that (5/16 ?) hose to be able to cut off the end, and be able to securely clamp it to the tank fitting again.
 
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HerbertFriedman

Member III
Loren, I did check the inlet hose where it is clamped to the fill port. I thought the hose clamp might be loose. It seemed tight but I was able to get maybe half a turn on the screw but saw no cracks or wetness there. My next step is to check the gasket and screws at the fuel gauge which is on the top of the tank about mid position. Will let you all know what I find.
 

Second Star

Member III
The only outlet that you haven't mentioned is the tank vent and line which should vent outside. Does it vent outside or does it have a split or cut in it? The only time it may get fuel in it is during a very full top off or a tight fit of the fill nozzle or funnel that forces fuel up the line.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Perhaps worth mentioning also is that I replaced all of the fuel system hoses over ten years ago. They develop cracks and leaks after a lot of years. Most mechanics I have met say that 20 years of service is more than you are entitled to expect from a reinforced hose.
 

HerbertFriedman

Member III
Loren, any special problems when you replaced all the fuel hoses?

I did look at the fill hose where it is clamped to the fill port, there may be a problem there, I need to fill the tank to overflow again and wrap an absorbent pad around the pipe. I have attached photos of the hose connections to the tank and the fuel gauge which also looks very dry. The only hose not clearly shown in the photo is the metal pipe which is probably the line to the fuel filter but that also looks dry.
 

Attachments

  • fuel filter and hoses, pdf.pdf
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Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Unfortunately it's kind of an unequal comparison. Our fuel tank is located under a settee, and the hoses are bit easier to see, albeit having their own difficulties to get at. I hope some owners of sister ships can check in.
(Speaking of the fill hose... on our tank that 1.5" hose has to be double clamped to the tube before the tank is fully slid into place. The other three hoses have to be led into their final area in preparation for the tank being introduced into position. Actually the aft tank under the aft berth on the BK Ericson's might not be much easier or harder.)
The good news is that once all the work is done, it should be OK for another 20 years. Hopefully. :)
 

HerbertFriedman

Member III
Loren, thanks for the info. I am familiar with the location of the tank in the settee area of the Ericson Olsen 34, a friend at our club has one and just has had to replace it due to a pinhole leak. One question did you replace the metal pipe that probably goes to the engine or just the rubber hoses? Mine are hard to get to and I just might has the yard ($$$) to do that job.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
One question did you replace the metal pipe that probably goes to the engine or just the rubber hoses? Mine are hard to get to and I just might has the yard ($$$) to do that job.
i might be guessing wrong, but by metal pipe do you refer to a factory copper tubing run to the engine compartment? As built out by the factory we did have one of those, and a reinforced hose that led back to the tank for the return line,
I replaced both, years ago, with USCG certified fuel (multi layer reinforced) hose. That old OEM copper tubing looked pretty beat up from being pulled thru the bilge and other tight areas, perhaps be a guy on a Friday afternoon eager to get to the tavern at 5. Maybe. :)
BTW, I "explored and pioneered" a much better routing for both those lines and got them out of the bilge forever. It's tedious work, but not that technical; every hour that you invest puts approx $110. back into your wallet, per hour!

Edit: is your friend a sailor named "Charlie" ?
:egrin:
 
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JSM

Member III
Just had the same problem on our 34-2. Topped off prior to crossing Lake Michigan from St. Joseph to Chicago. We were heeled over for seven hours. Once we were home the boat stank of diesel. Discovered that fuel had seeped from the fuel gauge over the top of the tank and into the bilge.
Not much but enough to stink things up. Hot water and Dawn to the rescue !
 

Alan Gomes

Contributing Partner
Just had the same problem on our 34-2. Topped off prior to crossing Lake Michigan from St. Joseph to Chicago. We were heeled over for seven hours. Once we were home the boat stank of diesel. Discovered that fuel had seeped from the fuel gauge over the top of the tank and into the bilge.
Not much but enough to stink things up. Hot water and Dawn to the rescue !
Add me to the list. The identical thing happened to me. I had to re-seal the gauge sender. The problem had not shown up until I topped off the tank and gave the boat a hard sail.
 

HerbertFriedman

Member III
i might be guessing wrong, but by metal pipe do you refer to a factory copper tubing run to the engine compartment? As built out by the factory we did have one of those, and a reinforced hose that led back to the tank for the return line,
I replaced both, years ago, with USCG certified fuel (multi layer reinforced) hose. That old OEM copper tubing looked pretty beat up from being pulled thru the bilge and other tight areas, perhaps be a guy on a Friday afternoon eager to get to the tavern at 5. Maybe. :)
BTW, I "explored and pioneered" a much better routing for both those lines and got them out of the bilge forever. It's tedious work, but not that technical; every hour that you invest puts approx $110. back into your wallet, per hour!

Edit: is your friend a sailor named "Charlie" ?
:egrin:
yes, Charlie is the person, apparently he told me that you and he had several conversations since you both have the same boat. I met Charlie via an on-line post that I saw concerning access to the bottom of the rods that support the shrouds. There is no easy to get to the bottom where the rods attach to the hull and was curious as to how to inspect them. Turns out some surgery is needed.

The metal pipe to which I was referring seems to be the one feeding diesel to the engine. It is attaches to the tank using what looks to be tapered, threaded fitting, I can see the teflon tape sealant. Mine does not look "beat us" and I see no sign of a leak so I was going to leave that alone.

However according to the next two responses, along with Christian's experience, looks like I need to look more carefully at the gasket seal on the fuel gauge.
 
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