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Discussion Starter #1
I bought a Scanmar 35 in Norfolk back in May and motor sailed her 180 miles to her new home near Chestertown. The boat motored well all the way there but now I am finding the fuel tank is spewing watery debris infested fuel into my fuel lines. It takes mere minutes to foul the water separator. Fuel gauge read about 1/3 tank and I have a 40 gallon tank. This weekend I will check the accuracy of the tank gauge to be sure I am not sucking sediment off the bottom but that aside there is an awfully lot of sediment in the tank. I do not believe this is the case as I sucked out 5 gallons of fouled fuel out until the fuel appeared to be running clean last week. Took the boat out and after about 45 minutes, sure enough, fouled the filter stalling the engine. My questions:

1. Somewhere along the way some genius T-d the HOLDING tank vent hose into the fuel tank vent hose. If the holding tank became full (which it did) would it be likely that I could have inadvertently pumped waste from the holding tank down into the fuel tank? Brings new meaning to "my engine is running [email protected]%ty" :)

2. How can I get the sediment out of tank since draining fuel off did not alleviate the issue?

Any and all help/suggestions welcome.

Mike
 

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the pointy end is the bow
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I recently went through this with our boat. In our case, the 1.5 inch fuel filler fittings were accessible on top of the tank. When I removed the hose and fittings, I could pump out almost all the fuel. I then used a stick with a rag attached and swished the bottom of the tank around and kept pouring in and pumping out the fuel. On the upper tank, I was able to finish the job by pouring some hot soapy water in the tank, swishing it around and then using a wet/dry vac with a small diameter vacuum hose, vacuum it out. That tank bottom was pretty clean when I was done. I couldn't do that on the lower tank, but got the crap down to a level where it's no longer being picked up by the fuel pickup tube.
 

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Discussion Starter #3
Thank you Ray. I was thinking about finishing the pump-out then a shop vac then rags. It's nice to know someone else was successful with this approach.
 

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Mike
1. never use a pump that is not rated for moving fuel. Sparks can happen any time.
2. separate the vents. That could be a lot of your problems.
3 We did a major diesel tank cleaning a few yrs back and used a product called Marine Clean. It is water based and biodegradable safe. The tank looked like it was brand new when we were done. here is a link: POR-15 Cleaner Degreaser

Peter
 

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Used to do same as Ray by accessing thru/removing fuel gauge...pumping out and cleaning with stick and rag. Finally bit bullet and cut a 5-6"? hole in top of tank and made my
own solvent resistant cover out of heavy cloth backed rubber. There are commercially available access cover available also. Makes for easy clean up
and not so dreaded job every few years.
And would separate vents sooner than later!
 

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Discussion Starter #6
OK Justified so it sounds like I SHOULD NOT try to suck fuel out with Shop Vac prior to stick and rag method. I used a hand pump made for changing oil to get the first 5 gallons out. Do you see any issue using this method other than tired sore arms?

By the way - Thanks!
 

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Discussion Starter #7
Hugosalt thank you for the clever idea for down the road.

By the way, already disconnected the waste tank hose and will install new vent next time I am aboard.
 

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the pointy end is the bow
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OK Justified so it sounds like I SHOULD NOT try to suck fuel out with Shop Vac prior to stick and rag method. I used a hand pump made for changing oil to get the first 5 gallons out. Do you see any issue using this method other than tired sore arms?

By the way - Thanks!
I should have been more clear, I used a hand pump to remove the fuel and the shop vac to remove the hot soapy water. The hand pump wasn't tiring like it can be pumping thicker motor oil. I removed 35 gallons all together. After letting it settle out at home, I put all but 5 gallons back in after filtering. There was five gallons of black watery sludge that went to the hazardous waste site.
 

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An inspection plate could be installed if there is access to the tank top. In my case the tank is installed under the cockpit sole so that wasn't possible. The new tank I had made has a drain at the bottom on one side so if I have to I can drain the tank and any sludge easily.

The combined holding/fuel vent was a very bad idea.
 

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Discussion Starter #10
I haven't visited for a while. I wanted to thank all for their input. I am going to tackle this job over labor day weekend. Ray - Any thoughts on securely attaching rags to a broom handle? I sure would not want to lose a rag in the tank.
 

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Given that you KNOW the fuel is contaminated with bacteria, I would not re-use any of it.

The old diesel can go to the MD MES sites as used oil (my company collects the used oil, so diesel is OK, justnot gasoline).

After a good cleaning I would start with BioborJF to keep the bugs down and to sterilize the parts (lines) you could not clean.

And in addition to a separate vent (yup, the T was one of the more bone-head things I have ever heard) I would install a vent drier; look at H2Out, Vetus, and my blog (search silica gel gasoline). Mount it in such a way (high with anti-splash valves on both sides if needed) that neither water nor fuel can enter the filter. I've seen measureably drier fuel since using a drier.
 
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