Fuel tank cleaning

[kerrye]

Couple of issues. My main fuel tank hasn't been cleaned so the secondary tank is one way to avoid cleaning it. I realized a person won't actually have to pump the secondary tank full because the return line will have to be plumbed to the secondary tank in order for it to function correctly. So in order to fill the secondary tank, a person needs just to close the return line to the main tank, open the return line to the secondary tank, run the engine and filtered fuel will be delivered to the secondary tank from the main tank via the filter and engine.

[smacksman]

But how can you run the engine from the main tank, in choppy conditions, to fill the day tank. The crud stirred up in the main tank blocks the fuel line/filter.
If your main tank is clean enough to supply fuel in all sea states then the day tank is not needed - other than a good backup.

[kerrye]

Correct. I don't intend to run it on those conditions. 5 gallons is enough for approximately 10 hours of operation on my A25 so as long as the tank is full at the beginning of a day, it should work as an alternative tank if crud gets stirred up in the main tank. I don't foresee a lot of multi-day passages in my future.

[smacksman]

Kerrye, that then sounds like good 'insurance'.
5gals = ~50lb shouldn't affect your trim. Offset it with a case of beer!
Roger

[kerrye]

One mistake I made when I ordered the tank is that I forgot about the need for a return line to the tank. I'll have to figure out where to put the return line. Perhaps drill and tap the cap for a fitting. I should have checked to see of they sold tanks with two fittings. I know they sell tanks with one fuel hole and a fuel gauge hole.

[glk34]

One last note. I have removed our A25 fuel tank on 2 occasions. Very simple. The only slow part is removing the fuel before removing the tank. Very easy access. Took less than a day. Rinsed out the tank, and than you know exactly the condition. There is a nice size inspection port so you can view most of the insides. It is so nice when you know you are starting with a clean tank.

Iron Jack.

[kerrye]

Where was your inspection port? I don't see one on my tank.

[BrookeMarie]

I am a new owner of a 25 with 2gm20 yanmar. Took her on her maiden voyage yesterday, seas became a little rough and she started to miss and sputter. I turned around and made it back to the dock. Primary filter and water seperator were full of crud. I pumped fuel directly from the tank into a clear water bottle. The milky dyed red fuel settled an inch of water on the bottom. Drain, remove and rinse the twenty gal tank is my plan. Your posts help, thanks. ( sorry for novel).

[Beta Don]

One mistake I made when I ordered the tank is that I forgot about the need for a return line to the tank. I'll have to figure out where to put the return line. Perhaps drill and tap the cap for a fitting. I should have checked to see of they sold tanks with two fittings. I know they sell tanks with one fuel hole and a fuel gauge hole.

For my single cylinder Kubota diesel genset I bought a 12 gallon aluminum tank on eBay for $50. It only had one fuel port, so I installed a tee fitting on the 5/8th vent line and inserted the 1/4 fuel return into the tee. It's probably not Coast Guard legal doing it that way, but I don't see any danger doing it that way either

Don

[kerrye]

I am a new owner of a 25 with 2gm20 yanmar. Took her on her maiden voyage yesterday, seas became a little rough and she started to miss and sputter. I turned around and made it back to the dock. Primary filter and water seperator were full of crud. I pumped fuel directly from the tank into a clear water bottle. The milky dyed red fuel settled an inch of water on the bottom. Drain, remove and rinse the twenty gal tank is my plan. Your posts help, thanks. ( sorry for novel).

Glad you made it back. If you can document what you do with some pictures and post them here, I think a lot of us would be interested.

[glk34]

As I recall, you can remove the level sending unit and get a good look and also a bit smaller plug that is located about 2/3 to the rear of the tank. I realize all the tanks are likely a bit different after 40+ yrs of mods and different owners but my point is that you should not shy away from removing the main tank and getting it cleaned out. Could be just crud but also could be rusty inside. Now is the time to find out not out on the water in a blow. By the way, I used 2 gallons of methyl hydrate to flush the tank out. The methyl will evaporate after a few hours of air dry and seemed to rinse the crap out of the tank. Looked like muddy water after the first flush. After 3 good flushes the methyl came out clean.

Iron Jack

[kerrye]

Update on my second tank. Got the 8x26 tank today. It fits between hull and liner to the starboard of the helm seat. Two mounting brackets will screw to the two pieces of wood glassed to the hull for the heater mount. Once it arrived I realized I could install the return line on the neck below the fuel cap. Drilled a hole thru the neck and stuck a 1/4" barbed fitting thru the hole. Put a short piece of hose on the inside so the returning fuel would go down into the tank and not directly across to the other side of the neck and another piece of fuel hose on the outside, capturing the fitting in the neck between the two hoses. It it leaks around the barbed fitting (which I doubt since it's high in the tank and the hoses are pushed up against the neck wall), I'll epoxy the barbed fitting in place. I decided to put a filter on this tank as well as the main tank so ordered a Racor R12T. I'll run the feed line to main fuel line downstream of the main tank filter and the return line into the main tank return line. Got petcocks to control which lines the fuel runs thru. General plan is to run the engine from the main tank and divert the return line until 'day tank' is full (I'll need to calculate the flow and then use a kitchen timer to remind me to shut if off when full). With both tanks full I'll have a choice which tank to use depending on which petcocks I open and close. If the day tank will gravity feed thru the racor filter, when the boat is not in use I can drain the day tank into the main tank and not leave any standing fuel in the day tank since the day tank is about 15 inches above the main tank. If the day tank will gravity feed thru the Racor, then even if the electric fuel pump fails, I still should be able to gravity feed fuel to the engine from day tank.

[2manyboats]

Kerrye

If the barbed fitting doesn't work out, check Hamiiton Marine. Moeller; elec. sending unit with diesel return.
Hamilton Order # 743130 $49.49 (2015)

Fits 6" to 24" deep tanks simply connect the fuel return line

Wayne

[kerrye]

Got the day tank installed. Don't have the fuel lines run yet. It's not perfectly level. The wood pieces glassed into the hull to which the brackets are attached are not themselves perfectly level. Hence the slight angle. I had to cut about an inch off the top of the bulkhead between the hull and liner. This tank is 8x26. The space where it sits is much longer. You might be able to get an 8x30 in there even though the space is longer. The challenge is working the tank into place in the space with the brackets installed. The 8x26 was tight but doable.

[Beta Don]

As an addition to this 'clean your tank' thread, I'll inject my recent experience

My A27 tank was removed & professionally cleaned by the previous owner. I found the receipt & they did a terrible job of replacing the aft cabin drawers so I'm 99% sure it was done

They cleaned, conditioned and treated the fuel & put it back in the tank. When I got ready to use the boat about 15 years later, I emptied the tank, discarded the old fuel, removed the tank sender & swabbed out the center tank section which you have access to via the sender hole with a white washcloth. The tank appeared quite clean to me

But, just to make sure I didn't have any problems on our 5,000 mile trip, I bought and installed a Parker/Racor 500 fuel filter to replace the smaller Racor filter which came with the boat. The smaller Racors with the metal spin on filter elements use pretty expensive replacement elements - $25 to $30 each while the 500 uses a $10 element & has a much higher capacity

Anyway, at about 250 engine hours I was pushing the engine pretty hard bucking a 2 knot current and at 2500 RPM's the engine began making a little hiccup noise every couple minutes which startled me a bit, but I thought I knew what it was. I reduced RPM's to 2300 and it went away . . . . for 3 or 4 hours anyway and then it began again. I reduced to 2100 for the remainder of the day

Yup - My Racor 500 element was covered with a black muddy substance and there was a good deal more of it in the bottom bowl. 99% sure the black gooey stuff is diesel algae, or the dead remains of it. Changed out the $10 element and all's well again

I assume if it took 250 hours to plug up the first filter element it will probably take even longer for the second one? We'll see!

But i guess this is a lesson that even a supposedly 'clean' tank can have enough residue in there to cause you a problem down the road. Filter well and treat your diesel with an algae treatment if the fuel will be in there for more than a few months

Don