Diesel in the Bilge - need your help

Duke · May 10, 2013

If you have been sailing since topping off on fuel, a steep angle of heel could be exposing a bad gasket around an opening in the top of the fuel tank, such as, inspection ports, possibly the fuel sensor or even the fuel fill line connection. There could also be a pinhole leak in the tank itself.

Captn Scotty · May 10, 2013

Did you check the vent hose from the fuel tank? It might have come away from a fitting at either end...Just a thought.

Don S/V ILLusion · May 10, 2013

davidpackwood said:
If there is a leak in the fuel tank does it drain into the bilge?

Yes.

I assume you removed the hatch on the port locker and inspected the tank top and hose connections?

Absent any obvious source, the tank is aluminum and therefore might be leaking. Albeit awkward, have you tried feeling, wiping or looking around below the tank from the aft cabin bulkhead opening?

Alternatively, have you run the fuel line to the engine and checked for leaks? The primary fuel filter is also right under the mattress and may be leaking.

onecoolair · May 10, 2013

davidpackwood said:
So I finally got rid of the head smell...now their is a really strong smell of diesel in the boat. The only thing we have done recently was fill her up with diesel. We now have some diesel in the bilge, How does it get there??????????

I have checked the engine, but there are no leaks anywhere.
The smell seems worse in aft cabin, especially with the ac on??

The admiral will not sleep on the boat while there is such a strong smell.

I have cleaned out the bilge and added :Citrus bilge cleaner" from westmarine??

I would like to know how the diesel can get into the bilge and how can I trace where it is coming from, your HELP is greatly appreciated.

Last year some friends who happen to just have a boat just like yours had this problem. It turned out to be the old aluminum tank located in the port stern locker, it had developed a small leak in the bottom of tank. Old aluminum tanks do this. So they carefully drained the tank themselves and removed it. Then they had a local shop do a repair.
Something else to be a where of.
They also had problem with air conditioner drain pan in the main cabin rotting out the teak floor and had to replace floor. To fix this condensation pan over flow problem they followed my leed and installed venturi tubes in the discharge lines of both a/c units.

Mike H. · May 13, 2013

We had the exact same problem on our 94 Vision 36.

I searched and searched for the leak. The diesel would appear after healing steeply or after a fill up. It was not the engine, it was not a tank fitting, it was not the vent hose. I could not see the fill hose, so I stuck my cell phone camera in the small space under the lazarette floor and over the tank. The picture showed diesel on top of the tank and under the fill hose.

It is impossible to replace the fill hose without cutting open the lazarette floor for acess to the hose and clamps. I had to cut a section of the floor away, replace the hose and reinforce the floor opening with an aluminum plate.

The hose had been crushed between the lazarette floor and the top of the tank during construction. After 18 years the hose developed leaks in the stressed section and began leaking during fill ups and healing when the diesel backed up into the fill hose.

Obviously a design and fabrication flaw.

I'll bet you $ 1.00 you have a similar problem.

Rick D · May 13, 2013

Agree With Don...

Check all the area under the tank by removing the access panel from the aft stateroom bulkhead. See if there is fuel on top of the tank to determine if it is a fill or suction/return connection or fill hose. Check under the mattress for the primary fuel filter (which would be my bet). I suggest you put oil absorber pads under/on each to leave in place a while. then, clean the area under the engine thoroughly and put a pad under it too. Check all the line connections, the secondary filter and fuel pump. It has to be somewhere in that system. BTW, if they have not been changed recently, this would be a good time to change out the primary and secondary fuel filters.

Tantor · May 14, 2013

I don’t want to highjack this Topic, but
can you please explain a little closer how did you do venturi tubes in the discharge lines for a/c unit?
Thanks,

onecoolair · May 14, 2013

Tantor said:
I don’t want to highjack this Topic, but
can you please explain a little closer how did you do venturi tubes in the discharge lines for a/c unit?
Thanks,

Fixing to head to boat... PM you later. Or maybe start new thread.

splax · Jun 1, 2013

I filled up for the first time Friday and had the same issue, and a friend noticed diesel on the cabin sole by the galley stove. I investigated and noticed diesel on the hull behind the cabinetry. There is a plastic vent hose on the fuel valve on the top of the tank. I think the fuel forced its way through the hose before coming out the vent outboard aft. I have not investigated further, so I could be wrong.