A27- Fuel Tank Removal & Install

[JT48348]

Here's how you remove your fuel tank:

1) Strip the entire aft cabin of headliner,trim, and wall panels. Remove the step and the boards that separate steps from tank area.

2) unscrew the tank from the mounting blocks which keep it off the floor.

3) Disconnect all your fill/fuel lines and vent hoses.

4) If your lucky and the tank has been removed before there may be notches cut out of the aft cockpit deck stringers so the tank with fittings can slide out. If not you may need to grind away some fiberglass so the tank has clearance to come out with the fittings. Some fittings are removable but the larger fill and venting are not.

Note: My tank has a builder plate from AFP tanks. Listed at 73 gallons. On the bottom of the tank I found red marker handwriting which reads "Albin Maine" and "73a" and also "1 of 7"

I pulled the fuel gauge and tried to look inside. Looks like black sludge. I'm curious if there's baffles inside. I plan to install an inspection/cleaning port. Anyone done this?

[JT48348]

More photos of the fuel tank space.

Looks like the engine room has been glassed off from cockpit lazarrets and aft cabin.

I'm thinking of a adding a bulkhead each side to separate lazarrets from aft cabin.

[Beta Don]

I'm a bit surprised - I *thought* most Nissan 6 cylinder equipped boats used dual fuel tanks, one under the port lazarette and one under the starboard. Your arrangement looks similar to the early Lehman/Peugeot equipped boats - Similar, but not the same

Is your fuel gauge electric, or is it a sight gauge? Mine is electric. I replaced the sending unit and hooked mine up to a digital, 13 segment LED readout - I bought the guts of it from a guy in South Africa http://www.eandsengineering.co.za/wp-co ... ual-V3.pdf
The gauge is user calibrated for full, 1/2 tank, low warning (any point you like . . . . 5 or 10 gallons remaining, the last couple segments of the gauge flash) and empty. It doesn't come with the display - I used a 13 segment bar graph like the one he shows in the user manual. With 13 segments, it's roughly 5 gallons per segment

Mine doesn't have that forward fiberglass box shown in your first nd last photo above, so my tank sits flush up against the backside of the engine room bulkhead. My boat has a built-in chest of 4 drawers mounted aft of the tank accessible from the aft cabin. My tank is 70 gallons but all of the fittings are on the top of the tank. Once you remove the rear chest of drawers, the tank easily slides out into the aft cabin. I say 'easily' though I've never done it . . . . the previous owner did. The finished fiberglass floor of both lazarette extends all the way across the boat and the tank sits on that and is bolted down on 4 wooden blocks, 3 screws in each 'leg'

Don

[JT48348]

Right mine is similar to yours, Don.

But I have a manual sight gauge. I have no draws in the rear cabin. Just steps. Two tank fittings are removeable 90 degree hose barbs probably 1/4-3/8". The larger fill and vent fittings are permanent.

[Beta Don]

Mine was removed, cleaned and reinstalled about 15 years ago - The boat hasn't been used since. They 'reconditioned' the 40 or so gallons of red dyed diesel and put it back in the tank. Not wanting to run 15 year old diesel in my new engine, I pumped it all out and disposed of it - It was *probably* OK to burn, but I didn't want to take a chance, besides, I needed it empty to calibrate my new fuel gauge. They must have treated it very well, as my tank is still clean as a whistle . . . . no sign of any sludge

The sending unit hole in the top center of my tank (same place as yours) is about 3 inches in diameter - You can get a small hand (not mine) down in the tank and also see inside pretty well if you lower a light bulb down in the tank

That black sludge you're referring to is algae. It grows in diesel tanks if any moisture is present . . . . it feeds on the diesel. My Dad had a 60 gallon auxillliary tank on his RV toter which he didn't take very good care if. By the time he addressed the problem, there was almost 40 gallons of sludge (algae) in the tank. If your tank is going to sit for long periods without much use, it's a good idea to use a biocide to prevent algae growth. I use Hammonds BioBor http://www.amazon.com/Hammonds-Biobor-D ... el+biocide

Don

[JT48348]

Do you think there's baffles inside the tank

[Beta Don]

Don't think so - At least I can't see any. My fuel gauge has a long swinging arm and it doesn't hit anything . . . .

Now that your tank is out, you might examine the exterior very carefully - If they welded in any interior baffles, you should be able to see signs of the weld on the tank exterior

Don

[JT48348]

Upon further inspection I've discovered that there are indeed two baffles creating three chambers inside the tank. The fuel gauge hole is just 2" on mine and I dropped a light inside to discover the tank is filthy with algae and it will be a serious cleaning job. Sorry no picture as the hole is too small.

I'm considering cutting three access ports to be able to clean each chamber and scrub it clean. The only commercial access port I could find is Sea Built and they run $150-170 for a single 6" round port. To me it's cost prohibitive.

I'm considering cutting my own ports approximately 5-8" rectangle with rounded corners. I would make my own alum covers out of 1/8" plate. I would tap and seal the covers just like the fuel gauge with a gasket or sealant.

The tank is 1/8" thick and the fuel gauge is mounted this way. So I don't see why I can't do this DIY.

Can I use a plastic inspection port?

Any thoughts?

[JT48348]

Thinking 1/8" thickness is tough to get good threads

My next idea

[Beta Don]

Assuming you're going to cut the inspection ports in the top of the tank, I don't see why this wouldn't work

The USCG approved ports are very similar, but the inside ring is welded to the tank. I think oval shaped ports would be much easier to seal than rectangular ones. Your inside ring could be held in place with a couple of countersunk flat head screws and you wouldn't need to notch your cover

http://catalinadirect.com/index.cfm?fus ... ct_ID=2362

Why not cut round holes and make round covers for them and just have them welded closed when you're done with your clean out?

It *is* possible to thoroughly clean out a tank full of algae (even one with baffles) without cutting any holes - There are companies that do this every day. The clean out is done with chemicals. I think a 5 gallon can of acetone would probably do it. Pour it in, let it sit for 2 or 3 days, turn the tank so a new side is on the bottom, let it sit a few days and repeat until all sides of the tank have served as the bottom. If you have a truck or trailer, you could haul it around and the sloshing would speed up the process I'm guessing. My tank was cleaned without cutting any holes (though by a professional) and it's clean as a whistle. Worth a shot before you start cutting holes, IMO

Don

[JT48348]

What kind of tank cleaning professional am I looking for. I original thought of chemical cleaning but no idea where to look.

[Beta Don]

Diesel Fuel Doctor appears to have several locations in Michigan - Their headquarters is in Grand Ledge MI (517) 605-5788

E-mail torre@dieselfueldoctor.com and see if they can point you to someone local who can help you with your tank cleaning

Don

[JT48348]

Yeah I saw them. I can't wrap my head around Algea-x magnetic fuel polisher. ?! No thanks

I was hoping there's a way to soak and clean this thing with solvents or chemicals. But everything I've read indicates it's a manual job to get a clean tank.

I will keep you posted

[smacksman]

You said - 'I'm thinking of a adding a bulkhead each side to separate lazarrets from aft cabin.' I found that opening the deck locker hatch a bit helped a cross draught of air in my bunk aft when it was warm. It is also useful to have the extra length if you are over six foot.

Free State's main tank is marked 72 gal and I think original. It has at least one baffle that has come loose and when the motion is violent it clangs about in an alarming manner!
Dosing chemicals for the diesel bug are quite expensive. In the UK, the fishermen put in half a gallon of petrol (gas) every now and again which does the same job.
The bug lives in the water at the bottom of the tank, not the diesel itself. If the water can be draind off at intervals then the bug is not a problem.
If the tank can be removed, then washing with petrol (gas) works well; as it does with fuel lines and filter housings.
If the tank can't be removed, then a few gals of petrol in the bottom stirred up with compressed air and then pumped out or drained works well if repeated till the petrol comes out fairly clean. One of those cheap Chinese 12v fuel transfer pumps work well. Just be careful that the switch to operate the pump is spark proof or well away from the tank.
I have tackled the diesel bug on three boats using this method with complete success.

[Beta Don]

I was hoping there's a way to soak and clean this thing with solvents or chemicals. But everything I've read indicates it's a manual job to get a clean tank.

Smacksman says gasoline will do the job - If not, pretty sure acetone would do it

You've got it out of the boat and I'll bet you have a pick-up truck (you tow the boat with something?) so put the gas in the tank, put the tank in the truck and drive around with it for a few days - The sloshing action will break up the crud and you can pour it out one of the openings in the tank . . . .

Don