Fuel Filters in Series

[Hud3]

The Racor 500 MA that most of us use is rated at 60 gallons per hour (227 liters per hour). Your fuel lift pump is moving a lot less than that. I can't imagine you'd stress it by adding another fuel filter in series. If you have an engine-mounted filter and a racor, I don't see why you'd want another racor in series. On the other hand, the idea of adding a second Racor in parallel, with valving set up so you can switch filters quickly if the active one clogs, is a good safety measure.

[Irish rambler]

I'd go with Pete 7 on this one, I use a Caterpillar water separator/filter as a pre filter, works perfect. Much better though to get to the root of the problem and clean the fuel tank. I filter all fuel into the tank through an old pair of ladies tights and have a sump and water drain on the tank to remove any fine sediment or condensation. I work on the 'prevention is better than a cure' maxim. everyone has their own thoughts of course, maybe I'm too cautious.

[Ziggy]

Originally Posted by Hud3

The Racor 500 MA that most of us use is rated at 60 gallons per hour (227 liters per hour). Your fuel lift pump is moving a lot less than that. I can't imagine you'd stress it by adding another fuel filter in series. If you have an engine-mounted filter and a racor, I don't see why you'd want another racor in series. On the other hand, the idea of adding a second Racor in parallel, with valving set up so you can switch filters quickly if the active one clogs, is a good safety measure.

This is exactly right.

One problem with adding filters in series, is that when your engine stops, yo will not know which filter needs to be replaced. You can replace them all, but that just takes more time.

For the same reason, you should make sure that the pick-up tube in your diesel tank has no screen. A few years ago, my engine stopped offshore in fairly rough seas. I replaced both the primary and secondary filters, but that didn't help. Eventually we got to a sheltered harbor under sail where we picked up a mooring. It wasn't until the next morning that it occured to me to pull the pick-up tube out of the tank, and of course it was plugged with slime. Next season I replaced the tank and the new pick up tube was again fitted with a mesh screen (which I pried out).

The ideal set up is to have two primary filters in parallel, selectable with a valve. If you have no room for two primaries in your engine compartment or your budget, a single easy to replace primary with sufficient capacity is sufficient.

[Irish rambler]

I hope I'm not being a bore on the subject. All fuels in Europe now contain 10% bio-fuel(rapeseed), you may have to change a couple of pre filters initially after starting to use it but after that the tank is nice and clean. DO NOT be tempted to run on recycled chip oil as it contains minute traces of sulphuric acid and carbon, acid is more aggresive if subjected to heat and pressure, both conditions are found in the injector pump and injectors.
Hope these tips help a fellow shipmate somewhere.

[dohenyboy]

Tangentially related to this topic is the idea of a day tank. Big enough to hold 4-6 hours of fuel and higher than the engine, so it gravity feeds the engine.
Fill the day tank with an electric pump.
You will never have an engine stoppage again from clogs.

[SimonV]

I run a Perkins 4.108 which has a 2 micron fuel filter on the engine. I have placed 2 racor 500 mc filters with 2 micron eliments, these are placed in parellel. Being just 2 micron they will block up quicker than 30s or 10s but as I can quickly switch fron one to the other. which I have had to in the past. it is easier to change out the racors when needed and you can keep the engine going. Just make sure you change the blocked filter at the first opertunity or else you may be bringing a blocked filter on line when you least need to.

[Irish rambler]

Hi dohenyboy, yep, big ship practice is fine I have similar set up,original tank athwarships and engine feed from the bottom of the tank to stop vacuuming in a heavy sea's, 2 long range tanks low down in the keel, fuel delivered up via electric pump off a semi trailer refrigeration unit to the main tank. I prefer to eliminate the problem at source,rather than any remedial actions, tank cleanliness in my own personal view is the key to safe cruising (I have only one engine) in a motor cruiser.. Maybe I'm just too particular

[Dockhead]

Originally Posted by Irish rambler

I hope I'm not being a bore on the subject. All fuels in Europe now contain 10% bio-fuel(rapeseed), you may have to change a couple of pre filters initially after starting to use it but after that the tank is nice and clean. DO NOT be tempted to run on recycled chip oil as it contains minute traces of sulphuric acid and carbon, acid is more aggresive if subjected to heat and pressure, both conditions are found in the injector pump and injectors.
Hope these tips help a fellow shipmate somewhere.

Not all. Fuel sold in at least the UK for ocean use is exempt from the rules and may be 100% mineral. Bio-fuel is a nightmare in a cruising sailboat, where the fuel is not turned over often and water is left in tanks for long periods -- long intervals between tank cleaning.

[Dockhead]

Originally Posted by Irish rambler

I prefer to eliminate the problem at source,rather than any remedial actions, tank cleanliness in my own personal view is the key to safe cruising (I have only one engine) in a motor cruiser..

+1

I also have dual parallel Racors, which I can switch in a flash with one turn of a lever, the setup much recommended here.

However, it must be kept in mind, in my opinion, that this is no panacea. Whatever got stirred up in your tank -- no doubt at the worst possible moment -- which clogged up one filter, will quickly clog up the other. So this setup is not likely to give you the chance to just flick the lever and carry on as if nothing happened. The real purpose of this setup is to make it possible to change filter elements on the fly.

So if you have a bag of filter elements on board, you can lie in the engine compartment changing the off duty filter as the on-duty filter clogs up . . . And repeat until you make port . . .

It is no substitute for regular cleaning of the tanks and care in choosing where to buy fuel.

[Irish rambler]

Dockhead, apologies I was under the impression that all fuel sold in the UK was to FAME standards, except of course for big ship bunker fuel. I can just imagine the problems on a sailboat with bio fuel. Boat builders don't always put a sump and drain on the fuel tanks more's the pity. I cruise quite a bit and not to muddy the waters but I use my engine as a multi-fuel running on rapeseed, maize oil etc.

[Dockhead]

Originally Posted by Irish rambler

Dockhead, apologies I was under the impression that all fuel sold in the UK was to FAME standards, except of course for big ship bunker fuel. I can just imagine the problems on a sailboat with bio fuel. Boat builders don't always put a sump and drain on the fuel tanks more's the pity. I cruise quite a bit and not to muddy the waters but I use my engine as a multi-fuel running on rapeseed, maize oil etc.

You should tell about your experiences -- I have only heard nightmare horror stories about bio-fuel on boats, and if you have managed to make it work, this information will be of great interest and value to all of us.

No, boat builders in fact rarely put in either sumps or drains. I have neither, and besides that, have a single tank. So I can easily be well stuffed if I am not extremely careful with fuel. Luckily the British yachting lobby is pretty strong (thanks to the RYA, probably) and political pressure has made it possible for us to continue to have access to 100% mineral fuel, red diesel, and with tax breaks unavailable to Continental yachtsmen.

We pay excise only on the part of fuel which we declare to be used for propulsion (as opposed to cooking, heating, and generating electricty). So most of us pay about 90p a liter effectively.

Also the quality of fuel is quite good, at least on the South Coast. I only buy fuel 2 or maximum 3 times a year (680 liter tank ) and try to buy it always from the fuel barge in Cowes, where they are very careful with the fuel they take on, and scrub out the tanks every year.

I have my tank cleaned out every two years.

So far it has worked for me, but others have been less lucky

[s/v Jedi]

It is very easy to create a system in which you draw fuel from any container / tank. I am currently drawing from a jerry jug just to test this for fun.

What you need is a couple of miniature manifolds for fuel feed and return, with mini ball valves on each connection. You can then connect some hoses and put them into the jerry jug. I use a wooden tapered emergency plug to keep them in place. I use a small boost pump to draw the fuel through a filter and then pressurize the feed manifold with it at 7psi. But once primed the engine lift pump should have no trouble with this either.

You can use this for many things. The connection to the return manifold can be used to tap some clean filtered fuel with the engine or genset running to pump the fuel, which I use to fill a filter housing or get some fuel to clean something etc. But the main thing is that you can run your engine without needing your tank.

ciao
Nick.

[Dockhead]

Originally Posted by s/v Jedi

It is very easy to create a system in which you draw fuel from any container / tank. I am currently drawing from a jerry jug just to test this for fun.

What you need is a couple of miniature manifolds for fuel feed and return, with mini ball valves on each connection. You can then connect some hoses and put them into the jerry jug. I use a wooden tapered emergency plug to keep them in place. I use a small boost pump to draw the fuel through a filter and then pressurize the feed manifold with it at 7psi. But once primed the engine lift pump should have no trouble with this either.

You can use this for many things. The connection to the return manifold can be used to tap some clean filtered fuel with the engine or genset running to pump the fuel, which I use to fill a filter housing or get some fuel to clean something etc. But the main thing is that you can run your engine without needing your tank.

ciao
Nick.

A great idea which probably everyone should implement.

I loved your fuel system for Jedi, something the rest of us can only dream about. Maybe this is something more realistic!

[s/v Jedi]

Originally Posted by Dockhead

A great idea which probably everyone should implement.

I loved your fuel system for Jedi, something the rest of us can only dream about. Maybe this is something more realistic!

My fuel system might look complicated on the diagram, but most of the components are on every boat already. The manifolds are easily home build with some brass T's and nipples and micro ball-valves (use hydraulic rated thread sealant from Permatex or equal). The extra filter is small and can be put anywhere (and people are selling them here on CF most of the time) and the pump is tiny and so great to have for priming and boosting... and that's all.

For two tanks you need the 2nd pump for transfer of fuel between tanks, but as you only have one tank, you can just leave all that out.

ciao!
Nick.

[Orrjames]

A great idea I used while working in AK, where the water temp and air temp created a lot of water in my tanks. We installed a quick valve to drain the bowls. Remove the original petcock or plug in the bottom of your racor bowls and plumb in a ball valve with an attached hose for easy re-direction into a bucket. We also installed water sensors on the bowls which alerted us when water was building up. When the sensors alarmed out, I would send the deckhand down to the valves and he could drain the bowls in just seconds, worked awesome.