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Gunk in fuel tank - how much is ok?

3211 Views 6 Replies 7 Participants Last post by  Maine Sail
The plan was to remove the fuel tank and put an inspection port in the top but that didn't work since I didn't want to remove the stern to get the tank out. <G>

I've had zero problems with fuel filters/fuel system -- I've had the boat since May. Reading some posts here scares the crap out me with you guys talking about filters clogging, etc. I'm hearing that here in Alaska the algae buildup isn't as much of an issue I guess due to our colder climate.

I pulled the fuel sending unit and took a peek inside the tank. It looked pretty clean except for about 1 tablespoon of green snot that I cleaned out. Is that a normal amount of stuff? Enough to be worried? Should I be fearless with only this amount?

The fuel tank is now completely empty. (Waiting for fuel sending unit to arrive to replace the faulty one). Any harm in leaving the tank empty for the winter?

Thanks in advance.
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No harm in leaving the tank completely empty, it is partially full that you should be worried about.

A little gunk in the tank is normal. If it is green and slimy, that can be algae which is not good. Biocide will deal with this.

A good way to tell the condition of your tank is to cut open the fuel filter after you change it each time. By looking at what is in it, you can get an idea of the condition of the tank. You will always find something since diesel tends to have all sorts of junk in it.
I envy your tiny snotwad of green. We emptied the 380 gallons of diesel from our 5 full tanks when we took posession. I gave it away. I removed the inspection covers and found up to 5 inches of what looked like decomposed garden slugs in each with black crud covering all surfaces. The tanks are built in 3/16 inch thick 316 SS welded. I cleaned out the bulk with a putty blade and then sprayed them down with FAST ORANGE by the gallon. I let them sit for two days and power washed. 24 years of accumulated neglect. This probably explaines the bushel basket of spare Racor elements I found.
Just remember, that little wad of snot is alive and will grow if given a chance. You're really best off not having anything in the tank.

Leaving the tank empty is a good idea, but remember to clean the tank out properly before you re-fuel the boat the first time.
It might not have taken that long. That could grow in a season and might have ...

I envy your tiny snotwad of green. We emptied the 380 gallons of diesel from our 5 full tanks when we took possession. I gave it away. I removed the inspection covers and found up to 5 inches of what looked like decomposed garden slugs in each with black crud covering all surfaces. The tanks are built in 3/16 inch thick 316 SS welded. I cleaned out the bulk with a putty blade and then sprayed them down with FAST ORANGE by the gallon. I let them sit for two days and power washed. 24 years of accumulated neglect. This probably explains the bushel basket of spare Racor elements I found.
driven the PO out of boating. With that much snot, I doubt you could change the filters fast enough if it got bumpy.

I would definatly hit it with a biocide, to be certain. Cheap.
Sail Delmarva: Diesel and Biocides
If you can get the fuel sending unit off, you can get a fuel polishing hose into the tank and get a pretty good clean-out. If you have growies already, they will only get worse and adding a fungicide may result in debris collecting on the bottom of the tank and becoming a problem itself unless the tank gets as good a cleaning as possible beforehand. For what its worth, we have been using Star-Tron Enzyme fuel treatment for some while now and we seem to have less issues with fouled filters although whether that is so, or merely my imagination based upon my hopes for the material I can't say as yet.

N'any case, good luck!
In the next week or so I will be cutting open my 31 year old tank. Sol-Tron (before you could easily get it here) / Star-Tron has been used since the late 90's along with Bio Guard. It will be interesting to see the results of religious use of this stuff.
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