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Anyone done this to facilitate a quick swap of a plugged filter?

I have been a boat that has one, but the switching labelling was confusing which lead to a much worse situation.

Duplex filters are standard on marine diesels and ships. It's very common to have to swing filters when the pressure differential is too high across a filter. I've had to do it every time I crossed the Great Australian Bight due to rough seas stirring up the sediment in the tank and a lower fuel level.
A single lever duplex is the way to go but they are very pricey


You can do the same with two, 3 way valves and filters. Don't do the set up in the video, you need a valve before and after the filter, that will allow you to keep the engine running as you 'strip' the water out of the other filter.
You can make a system for about $1200, two small Racors (with metal bowl at bottom for fire resistance) and two three way valves from Pirteck.

I haven't have much luck with the Chinese copy Racors, they tend to suck air.

Even better is to empty and clean your fuel tanks every couple of years, then maintain clean fuel.

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EastCoastSail said..
Duplex filters are standard on marine diesels and ships. It's very common to have to swing filters when the pressure differential is too high across a filter. I've had to do it every time I crossed the Great Australian Bight due to rough seas stirring up the sediment in the tank and a lower fuel level.
A single lever duplex is the way to go but they are very pricey


You can do the same with two, 3 way valves and filters. Don't do the set up in the video, you need a valve before and after the filter, that will allow you to keep the engine running as you 'strip' the water out of the other filter.
You can make a system for about $1200, two small Racors (with metal bowl at bottom for fire resistance) and two three way valves from Pirteck.

I haven't have much luck with the Chinese copy Racors, they tend to suck air.

Even better is to empty and clean your fuel tanks every couple of years, then maintain clean fuel.

Thanks. Most of us already have one so we just need to buy another and do a little bit of plumbing with a couple of three-way valves.

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julesmoto said..

Thanks. Most of us already have one so we just need to buy another and do a little bit of plumbing with a couple of three-way valves.

That's what I did!!
Hopefully I can flick the valve before the engine completely stops & get across the bar or out of danger - because it won't happen when you are cruising along nicely!!

The premise of this switch over system is that the marine engine driver recognises the progressive deterioration of power, as at least in my experience a fuel blockage in the filter /pre filter system is a gradual episode. Tho the prudent would change over if in doubt to be sure

Electric solenoid valves so you don't have to go down into the engine room, maybe one switch for each filter controlling in/out, engine sounds a bit funny, switch over and see if it changes.
hang on only one valve per filter not one upstream

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bullrout said..
Electric solenoid valves so you don't have to go down into the engine room,

Now there's an idea!!!

I'm using electric solenoid valves for water but never looked at small ones for diesel.

The 3 way valve before and after the filter gives you more control. If you have taken on poor quality fuel in some developing country (sometimes you have no other choice), then you swing the filter to the good side, turn off the valves on the blocked side, change out filter, use the electrical lift pump located pre filter to bleed the filter with the valve after the filter closed. Then you have a cleaned, bled filter ready to go if the 2nd filter blocks.

When I experienced an engine failure due to a blockage it wasn't in the filters. I have a twin racor set up but that didn't help when I switched over filters because the blockage was in the lines before the filter.

As already mentioned best bet is to maintain a clean fuel and tank. I cannot access my keel tank to clean but I can treat it and I do "polish" the fuel although I know that is not a guarantee of getting the tank clean. My solution is to only use the keel tank as storage and run off the day tank which I know has no build up of sediment because I check it regularly.

I also have some cheap inline filters easily seen and changed that are directly behind the fuel pick ups to stop any large bits of snot getting into the lines. If I get a blockage again I should be about to locate it in about 30 secs., if its not in the filter it will be in the pickup. I have spare inline filters cable tied next to one in use ready for a quick changeover.

+10 for that Camm.

If you have the space for it, a day/service tank with X number of hours worth of fuel (depending where you usually operate) can really provide peace of mind.


Not always an option, but I am a fan of it.

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cammd said..
When I experienced an engine failure due to a blockage it wasn't in the filters. I have a twin racor set up but that didn't help when I switched over filters because the blockage was in the lines before the filter.

As already mentioned best bet is to maintain a clean fuel and tank. I cannot access my keel tank to clean but I can treat it and I do "polish" the fuel although I know that is not a guarantee of getting the tank clean. My solution is to only use the keel tank as storage and run off the day tank which I know has no build up of sediment because I check it regularly.

I also have some cheap inline filters easily seen and changed that are directly behind the fuel pick ups to stop any large bits of snot getting into the lines. If I get a blockage again I should be about to locate it in about 30 secs., if its not in the filter it will be in the pickup. I have spare inline filters cable tied next to one in use ready for a quick changeover.

Something translucent like these might be handy for a day tank although the smallest one seems to be 37 liters which is a bit big my needs and available space.

Day/ gravity tank has the advantage of, well gravity, if the lift pump gives out it don't matter. On my old boat the port & starboard fuel tanks are gravity feed. What could go wrong ? I've had a small accumulation of debris in the pre filter line, engine would continue to run but a serious lack of balls. Always a new trick

There seem to be quite a few options for small cheap day tanks that would fit in tight spaces as below. I wonder how small is too small and what type of lift pump to use?

I just bought a 12v fuel pump off repco to supply the generator, the engine seems to do fine on it own. For transfering/polishing fuel I bought one of these

www.scintex.com.au/collections/electric-12v-pumps/products/diesel-transfer-gear-pump

because its a gear pump you can adjust the flow with a simple ball valve on the intake side.

That stainless day tank looks good but it needs a fuel return inlet and a good size breather (for filling from the main tank when underway).

The plastic tanks above could be a potential fire hazard in an engine room.