Bad Fuel Problem

[ashefrin]

I recently purchased a 1980 Hatteras 53 Convertible and the previous owner left us bad fuel in the rear tank, we are trying to remove 700 gallons of contaminated fuel from the rear tank.
The Marina does not want to take apart the cover(see picture) and remove the sending unit because it has never been removed They also say that if I get the bad fuel pumped out at a cost of $8.00 per gallon they cannot guarantee that there will not be a lot of sludge in the bottom and how to get it all cleaned out is my question is how do I get all the sludge out of the tank. I am having someone from an environmental company come safely remove the old fuel but he cannot be sure if he gets all the stuff out of the bottom of the tank.
My thoughts are to drill a 2” hole to the right of this cover and then seal it up after I get the tank cleaned out. Any suggestions would be helpful……Thanks in advance 20210303_095720.jpg

[Pascal]

I wouldn’t remove the plate but the gauge sender should come off and will be enough to suck the sludge at the bottom. That s what we did on my boat during the repower to ensure clean tanks.

Unless the fuel is real old, most of it could be pumped away from the bottom and be filtered. That’s why you need to pull the sender so you can pull from the top first to check it

[ashefrin]

I wouldn’t remove the plate but the gauge sender should come off and will be enough to suck the sludge at the bottom. That s what we did on my boat during the repower to ensure clean tanks.

Unless the fuel is real old, most of it could be pumped away from the bottom and be filtered. That’s why you need to pull the sender so you can pull from the top first to check it

Thanks for the idea I will check it out....appreciate it.....

[Boatsb]

Pull all the fittings.. Unscrew the plate. Fix the broken screws and retap where necessary. There's no reason not to fix the thing right while your at it. Shortcuts never pay off.

Get a fuel polish company to clean and remove the bad fuel. It's not a DIY job. Too much to go wrong with transportation of 700 gallons of bad fuel.

[Pascal]

Make sure the boat is blocked so that the fuel pools under the hole when almost empty. Had this issue on mine. I had about 100 gallons old fuel removed. They got it all out of the forward tank but because the boat was blocked slightly now high there were about 20 gallons of old fuel and crap left in the aft tank. I was able to pump it out and filter it once in water

[bostonhatteras]

I seriously doubt you'll have deep sludge. Unless the PO was pouring waste motor oil in there in ridiculous concentrations I cant see where the sludge would result from. What you'll likely have is a fair amount of bacteria spores. Water in the tank will also cause the copper pick up, return and screens to corrode. What I personally did to a tank with problems such as I just mentioned was to use oxalic acid to clean the tank. Its no simple task unfortunately as you'll need approx. five dry gallons of oxalic acid powder placed into the emptied tank followed by 50 gallons of tap water. Let the acid sit for a couple days and if you can take the boat out and let it splash around. Pump all the acid out after and flush the tank a few times with clean water. Using a simple impellor pump is sufficient to remove the water and debris. use a vacuum cleaner to suck up the remaining water the pump wont get. to dry the tank, take a 2" plastic pipe nipple and a 2" flange and fasten a bilge blower to the flange. Screw the pipe nipple into the fuel gauge fitting and operate the bilge blower pushing air into the tank. Remove the deck fill cap to allow the moist air to escape. its a long process but it works with out cutting any holes in a perfectly good tank. dont try looking in the tank with a flashlight, its just a source of frustration. instead use a medium base lamp holder from an old clamp light and screw in a candelabra style bulb.. this will slip right into the 2" fuel gauge threaded hole and you'll be able to see everything really clearly.

[jim rosenthal]

You might also invest in a cheap fiberoptic 'endoscope' which will allow you to see all the areas of the tank. HF has them, and they are very useful.

[ashefrin]

Pull all the fittings.. Unscrew the plate. Fix the broken screws and retap where necessary. There's no reason not to fix the thing right while your at it. Shortcuts never pay off.

Get a fuel polish company to clean and remove the bad fuel. It's not a DIY job. Too much to go wrong with transportation of 700 gallons of bad fuel.

Thanks a lot for the advice.....appreciate the help

[oscarvan]

Many auto repair shops up here burn waste oil in their shops in winter. They will happily take your dirty fuel and cut it into their barrels.

[Glory]

Did you a the fuel tested?

My boat came with 300 gallons in the aft tank that had been there for more than ten years. PO Claimed the fuel was NG, I burnt it. Away from the harbor, and ready to switch to another tank, I used a couple of racors in the process. But didn't pay to remove it.