Diesel in water lift muffler

[NICK1951]

Hello Maine and others,

I recently, winterized the 1984 Catalina 36 with a Universal M-25. I opened the drain on the water lift muffler and subsequently found about a cup of diesel in the bilge. I am sure it came from the muffler. Questions:

1. Is this dangerous?
2. Is there a risk of the diesel igniting a fire in the manifold, pipes or muffler?
3. Why would so much diesel accumulate in the muffler? Diesel is lighter than water, should not it be pushed through the muffler generally before the water?
4. What would cause this?
Thanks Nick

 

[centerline]

1... not dangerous in itself, but the main problem that allows it to happen could be harmful to the engine
2...no
3...diesel IS lighter than water. it got in there after the engine was shut off so there was no pressure to push it out.
4... dirty or faulty injector nozzle(s). but it would be more like a tablespoon or two rather than a cup.

there is still pressure behind the "injectors" after the engine dies, but if they are dirty, they may not hold the pressure in them and will leak the fuel into the cylinder(s)....and if the exhaust valve is open, it can run out into the exhaust manifold.
but there is only a measured amount that can get thru this way, so if you truly do have a cup of diesel in the bilge, i would look at the lift pump, filter or fitting leak, AFTER the lift pump...
sometimes a lift pump will have a seal failure and the fuel will spill out a "weep" hole built into the casting, rather than being dumped into the crankcase...

 

[Stu Jackson]

found about a cup of diesel in the bilge. I am sure it came from the muffler.

Nick,

I'm not sure how you can be sure of that. The only "hole" in the muffler is the drain, right? Could you perhaps explain how you came to that conclusion, to help us help you?

 

[NICK1951]

Centerline and Stu
Thank you for your replies. The boat is on the cradle. The bilge is clean. I opened the drain on the muffler. The Muffler drains under the engine, kitchen cabinets and into the bilge. The engine has not been started. I check the bilge 1/2 hour after draining the muffler. Bilge has water and diesel. I never have had diesel in the bilge, previously. I do not believe it is fittings on the fuel pump or fuel filter because the engine was not run. Thanks for your thoughts.

Nick

 

[Stu Jackson]

Gotcha, thanks.

Consider, since we're not there with you, that the "diesel" you are seeing is a product of the last amount of combustion from the exhaust gases mixing with the raw water cooling from the HX.

It's part of that nasty crap that's usually sitting in the muffler, sight unseen.

While I have never had to "winterize" our boat, I'm am intimately familiar with Maine Sail's winterizing procedure, using a bucket for the raw water which could have antifreeze icnluded, so that the muffler need never be drained into or inside the boat.

Winterizing an Engine on the Hard (Thanks to Maine Sail) - NEVER connect a hose to your raw water pump inlet - NEVER!!!

http://forums.catalina.sailboatowners.com/showthread.php?p=873073&highlight=winterizing

Am I missing something?

 

[Charles Erwin]

It is impossible to have diesel fuel at this high a concentration originating at or within the water lift. Look for a diesel leak elsewhere.

Charles

 

[Davidasailor26]

Had you checked the bilge before draining the muffler? If not, my guess is that your fuel tank has developed a leak, and you just happened to notice after draining the muffler. I guess you'll know for sure if you go back to the boat and there's more fuel there again.

 

[NICK1951]

Thanks all,
For clarification:

Step 1
Engine not run for 1 week
Bilge clean
Boat on cradle

Step 2
Open drain on muffler for 1/2 hour
Close drain
Water drains from muffler to bilge
Go to bilge to remove water and find water diesel mixture

Step 3
Put raw water hose in bucket of antifreeze
Start engine run 3 gallons of antifreeze through system
Bilge clean after running antifreeze

Stu,
I prefer to drain the muffler first, in order to avoid a diluted mixture of antifreeze in the muffler.

Thanks all

Nick

 

[NICK1951]

I hate it when I am wrong and you all are right. Proves two or more heads are better than one. I started the engine on the hard (5/16) ran it for 3 minutes and it quit. Checked the bilge, it was filled with diesel, again. Fuel tank connections no problem. Primary fuel filter (Dahl) input connection had failed. It is a bronze barbed fitting. There was no stress on the fitting. Still dead on arrival. I suggest one carries extra hose, hose clamps, fittings and connectors.

Best to all,

Nick

 

[arf145]

And I love it when someone comes back to complete the story and tell us what they found! Plus, you've added to the knowledgebase by doing so. Kudos! And glad you got it fixed.