How to clean a fuel tank with no inspection hatch?

[pmagowan]

The problem is that to remove the crud you will have to give the walls of the tank a really good blast. Otherwise you will end up doing as above and simply making a couple of scrapes through it. Imagine trying to clean a filthy saucepan with a small tube through a hole? It really needs a scrub. I wonder if something could be done with a high pressure hose to blast the crud off the interior. You would need to undo all the pipes to allow the pressure out. You would either have to use diesel as the medium (I don't know if pressure washers can handle this) or you could use water and then use something to absorb the water residue once pumped out(I think acetone works). I don't think simply pumping it all out will really get the crud out as it will simply go to the bottom. This is why the hatch is the only practical option as you can get a hand in and literally scrub the tank. I completely replaced my old mild steel tank as it had crud, rust and no hatch. I now have a plastic job with hatch. No probs since.

 

[prv]

This is why the hatch is the only practical option as you can get a hand in and literally scrub the tank.

+1 - I used a Scotchbrite pan-scourer to remove the black deposits from the sides and bottom of mine. It took quite a bit of elbow-grease, no way you could do the same through a tiny hole except perhaps with steam or something.

Pete

 

[Cardo]

+1 - I used a Scotchbrite pan-scourer to remove the black deposits from the sides and bottom of mine. It took quite a bit of elbow-grease, no way you could do the same through a tiny hole except perhaps with steam or something.

Pete

Worry not, we are convinced we need to fit an inspection hatch. But this likely won't happen until we're settled down for the winter. I was just thinking of quick and easy interim solutions. I'm thinking not going out in bouncy weather might be a good solution!

 

[pmagowan]

Worry not, we are convinced we need to fit an inspection hatch. But this likely won't happen until we're settled down for the winter. I was just thinking of quick and easy interim solutions. I'm thinking not going out in bouncy weather might be a good solution!

yes, and some people do fuel 'polishing' which gets the crud out of the floaty stuff. Of course as soon as you bounce around any that is on the sides will re-suspend itself. Just make sure you have spare filters!

 

[prv]

2. One pump such as this:
http://www.ebay.co.uk/itm/like/3710...f11=ICEP3.0.0&ff12=67&ff13=80&ff14=108&ff19=0

I used a small electric pump from eBay to empty the remaining diesel from mine before cleaning. The listing claimed it was self-priming, but this was clearly a lie as it turned out to be a centrifugal impeller pump. Fine once it got going, but no chance of self-priming and I got a couple of mouthfuls of diesel trying to help it.

Do you know if the pump linked above will self-prime? I binned the old one in frustration even though it was fine within its limits, this one might be useful as a replacement.

Pete

 

[Chris_Robb]

Worry not, we are convinced we need to fit an inspection hatch. But this likely won't happen until we're settled down for the winter. I was just thinking of quick and easy interim solutions. I'm thinking not going out in bouncy weather might be a good solution!

Pmagowan is certainly right if the crud is thick. If the tank is shallow (as was the moodies tank), you can dig the crud out by hand. My solution is much more of a maintenance solution than a cure to a really bad tank.

As you say - avoid bad weather - but you will be caught out so have plenty of spare filters and get good at changing them at sea.

Does anyone know if a blocked filter can cause undo stress on the diaphragm of the engine lift pump? It would seem to me that it might push a ancient fuel pump over the edge.

 

[Chris_Robb]

I used a small electric pump from eBay to empty the remaining diesel from mine before cleaning. The listing claimed it was self-priming, but this was clearly a lie as it turned out to be a centrifugal impeller pump. Fine once it got going, but no chance of self-priming and I got a couple of mouthfuls of diesel trying to help it.

Do you know if the pump linked above will self-prime? I binned the old one in frustration even though it was fine within its limits, this one might be useful as a replacement.

Pete

Yes - its rubber impeller pump so it will self prime. If pulling from a large head then some lubrication might be sensible to avoid overheating. It also needs to run fast - my cordless drill would not run fast enough.

 

[prv]

As you say - avoid bad weather - but you will be caught out so have plenty of spare filters and get good at changing them at sea.

As I mentioned earlier, we tried to live with the crud for a season and a half. So we have several useful fuel system improvements that are still worth having even after cleaning the tank:

• Dual changeover primary filters - turn a valve and a new filter comes online. Change the old one when convenient. We have one of the absurdly expensive ready-made ones from ASAP, but I have also made my own (on a different boat) using copper tubing and two ball valves.
• Secondary filter moved from the engine to a more convenient bulkhead. Depending on your layout this might not be needed, but our engine-mounted filter was very hard to get at. Simple to do on the Volvo D series - undo two bolts and replace short hoses with longer ones.
• Manual priming pump - an outboard style bulb pump immediately after the tank, it can push fuel under positive pressure right to the injector pump and back down the return line. Makes changing filters really easy, just screw them on empty, open the bleed valve, and give a few squeezes until fuel comes out the top.
• Suction gauge - tee'd into the line between the primary filters and the lift pump, and mounted next to the companionway where I can glance at it as I go in or out of the cabin. As the primary filter becomes more clogged, the suction increases. Seeing a nice low figure before entering confined waters is reassuring! Also allows you to distinguish between a blocked primary or secondary filter (suction will read normal in the latter case) and avoid changing the wrong one.

We also used to get blockages of the dip pipe in the tank, this could be identified because the gauge was high and the bulb pump had collapsed itself. Without these items, the source of the starvation could have been anywhere in the system.

Pete

 

[prv]

Yes - its rubber impeller pump so it will self prime. If pulling from a large head then some lubrication might be sensible to avoid overheating. It also needs to run fast - my cordless drill would not run fast enough.

Thanks. Bit concerning about the drill, as I was planning to use the boat's cordless as the power source and thus have useful portability.

I tend to think of my 18v LiIon Makita as just as good as a typical mains drill, but the boat drill is an older 12v NiMH Makita and probably not as quick.

Pete

 

[oldvarnish]

As I mentioned earlier, we tried to live with the crud for a season and a half. So we have several useful fuel system improvements that are still worth having even after cleaning the tank:

• Dual changeover primary filters - turn a valve and a new filter comes online. Change the old one when convenient. We have one of the absurdly expensive ready-made ones from ASAP, but I have also made my own (on a different boat) using copper tubing and two ball valves.
• Secondary filter moved from the engine to a more convenient bulkhead. Depending on your layout this might not be needed, but our engine-mounted filter was very hard to get at. Simple to do on the Volvo D series - undo two bolts and replace short hoses with longer ones.
• Manual priming pump - an outboard style bulb pump immediately after the tank, it can push fuel under positive pressure right to the injector pump and back down the return line. Makes changing filters really easy, just screw them on empty, open the bleed valve, and give a few squeezes until fuel comes out the top.
• Suction gauge - tee'd into the line between the primary filters and the lift pump, and mounted next to the companionway where I can glance at it as I go in or out of the cabin. As the primary filter becomes more clogged, the suction increases. Seeing a nice low figure before entering confined waters is reassuring! Also allows you to distinguish between a blocked primary or secondary filter (suction will read normal in the latter case) and avoid changing the wrong one.

We also used to get blockages of the dip pipe in the tank, this could be identified because the gauge was high and the bulb pump had collapsed itself. Without these items, the source of the starvation could have been anywhere in the system.

Pete

It think that set up is about as good as it can get. I've got the primary changeover, and the outboard bulb for priming,and together with Racor filters it makes life very easy.

Moving the secondary is a good idea too, but I've never found that it clogs (Volvo 38hp)

 

[prv]

Moving the secondary is a good idea too, but I've never found that it clogs (Volvo 38hp)

I've twice had it block at sea. The first time was fair enough, as (for reasons connected with work on the saildrive) it had missed being changed the previous winter. But the second time was only about 20 engine hours later. My assumption is that the 10 micron primary filters were passing through finer crud that was being caught in the secondary. When I next stock up on primaries I'm going to buy the 2 micron version - since they're the ones on the changeover I definitely want them to block first.

Pete

 

[pmagowan]

I've twice had it block at sea. The first time was fair enough, as (for reasons connected with work on the saildrive) it had missed being changed the previous winter. But the second time was only about 20 engine hours later. My assumption is that the 10 micron primary filters were passing through finer crud that was being caught in the secondary. When I next stock up on primaries I'm going to buy the 2 micron version - since they're the ones on the changeover I definitely want them to block first.

Pete

It has always been my primary that clogged. I moved it to a good location and changed it to a Racor type. Much more expensive (I buy filters in bulk from ASAP) but it is very easy to change even while under way. You don't have the fiddly o rings etc falling into the bilge. I also put on a hand pump similar to those on outboard fuel lines. This helps prime it. Now I can do a filter change and prime in under 60 seconds.

 

[prv]

It has always been my primary that clogged. I moved it to a good location and changed it to a Racor type. Much more expensive (I buy filters in bulk from ASAP) but it is very easy to change even while under way. You don't have the fiddly o rings etc falling into the bilge. I also put on a hand pump similar to those on outboard fuel lines. This helps prime it. Now I can do a filter change and prime in under 60 seconds.

Exactly the same as mine, except that with the dual-changeover head the fast change (while equally possible) is not required

Now I just need someone to start making reasonable-quality copies of the Racor cartridges for less than the £20 a pop that ASAP want

Pete

 

[Chris_Robb]

Thanks. Bit concerning about the drill, as I was planning to use the boat's cordless as the power source and thus have useful portability.

I tend to think of my 18v LiIon Makita as just as good as a typical mains drill, but the boat drill is an older 12v NiMH Makita and probably not as quick.

Pete

Well it tends to be a once a year operation, and very often you will be ashore anyway, so you could beg, borrow an mains drill if yours is not fast enough.

Can I add a suction gauge to my existing Rocor filter?

 

[Chris_Robb]

Now I just need someone to start making reasonable-quality copies of the Racor cartridges for less than the £20 a pop that ASAP want

Pete

Isn't one of the reasons the Racor genuine filters are so expensive is that they prevent the passage of water? though I can't think how they do that.

 

[pmagowan]

Isn't one of the reasons the Racor genuine filters are so expensive is that they prevent the passage of water? though I can't think how they do that.

They do, as does their funnel. It is quite amazing to fill it with water and nothing goes through.

 

[prv]

Well it tends to be a once a year operation, and very often you will be ashore anyway, so you could beg, borrow an mains drill if yours is not fast enough.

Certainly I'm unlikely to be emptying the fuel tank on a whim, but it would be a useful general-purpose pump to have in the tool locker anyway.

At the price, I think it's worth a suck-it-and-see.

Can I add a suction gauge to my existing Rocor filter?

Yes - or any other kind. The gauge isn't added to the filter, it goes between the filter and the lift pump.

I bought a brass T-piece like this:

and screwed hose barbs into each leg. Larger ones (to match the fuel hose) on the straight-through ends, and the smallest I could find on the side arm. Then I cut the hose and inserted the fitting, also mounting it to the bulkhead with a clip. Obviously you can use different fittings to achieve the same thing, for example if your fuel lines are metal or if you happen to find a suitable tee with barbs as one piece.

The hose to the gauge comes off the side arm of the tee, and first runs upwards for several inches. This is to stop fuel running along it into the workings of the gauge - I don't actually know if that would cause a problem, but it seemed easiest to avoid it. The gauge came with a screw connection on the back, so again I bought a hose barb fitting to suit. The hose from the tee simply fits onto the back of the gauge, and the gauge is mounted in a convenient place. I had various engine-related bits I wanted to display, so I made up a neat little panel with fuel level, fuel suction, switch for the bilge pump, and a red LED that flashes if the hot water overflow bottle is full.

Looking back through my email, the gauge scale was 0 to -1 bar, stated as being suitable for air, water or oil, and cost all of four quid

Pete

 

[Sailfree]

Thinking of my own boat that has had 10yrs of charter use I am wondering about preventive maintenance.

Its a yanmar engine.

Anyone found a simple dual diesel filter set up that I can install preferably with diesel filters applicable to commercial vehicles that should be cheaper.

 

[Malcolm3]

I think one of the problems is the standard CAV filter is easily blocked. The diesel from the tank goes first to the paper filter and then to the glass bowl. Many tanks have crud in them though once its stuck probably doesn't matter and problem is where it isn't . I had a problem years back when diesel bug came in and was changing the paper filter every couple of weeks. I solved it completely by putting in a separator without a filter before the CAV filter and cleaning it annually. And occasionally draining a cupful from the bottom of the tank.

 

[oldharry]

If the tank can be removed (mine could with some difficulty) then the simplest way is to put about mugful of pea gravel in with around half a litre of fuel and shake it vigorously for several minutes. Remove the shingle. ( also not very easy!). Rinse out with fresh full, and you have spotless tank! No good if the tank is built in though!