Fuel polishing

[janders]

Hey all,

I'm interested in putting a fuel polishing system in place on our Caliber 40. We're going to be cruising far afield (Mexico for starters) where we'll get all sorts of bad fuel. We'd like to avoid fuel problems if possible.

Here's our current fuel system. We have a 55 gallon fuel tank (non-LRC Caliber 40). We have parallel Racor filters on the suction side of the lift pump. After the Racor outlets, we have a T in the fuel line leading to a little 12v pump that feeds our bulkhead diesel heater.

What I'd like to do is put in a T-valve after the 12v pump and run a line from the T back to the fuel fill or tank vent lines. I don't know much about the 12v pump other than it's just something that the PO picked up at Napa.

Anybody have a guess on what sort of PSI I'd need on the pump to pull the fuel through the Racors and get a decent enough flow to spin the particles out? Anybody know how to calculate the volume of flow so I know how long to run?

Another idea I've considered is putting a 2 micron element in one of the Racors and use that for polishing and as a backup. Then leave a 10 micron element in the other Racor and use that as the primary filter for the engine. I could still hot swap to the 2 micron Racor if I needed to although I don't know if the lift pump on our engine could pull fuel through a 2 micron element.

If you have any other feedback/experience with this type of system, I'd love to hear it. One bit of advice I got from diesel engine class teacher was to not polish fuel while running the engine since the polishing tends to aerate the fuel. Would not have known that.

Here's something I drew up in my boat notebook along with some notes from the discussion I had with my teacher.



Thanks!

Jason
s/v Hello World

[MJWEENZ]

Jason,
Try this link
Projects: Below Deck: Marine Fuel Polishing Solves Problems | MadMariner.com

[Pblais]

Personally, I would add dual Racor 500 filters / separators and forget about fuel polishing totally. Use the money saved for something you really need. The dual 500 is a sweet setup and it's easy to pop into place. The 500 series use the cheaper filters that cost 1/3 the price of the spin on filters. Be sure it's some place easy to get at. If you had 1000 gallon tanks you might think about polishing. For a 40 ft boat the dual 500 is overkill as it is. Add the vacuum gage where the T handle goes and you have a very complete system that can be serviced easily and you'll know before they need to be changed.

With the dual filters you can swap out a clogged filter in seconds. Note the fuel passing the filters is the same no matter how many times you filter it. For every three gallons of fuel you burn you send almost a gallon back through the return lines. You'll end up filtering it multiple times before you burn the last gallon with no polishing.

The US Navy runs polishing 24 x 7 even in port but they carry a few more gallons than you or I do. The expense of an extra pump and more fittings just leave more places to develop an air leak.

[janders]

Originally Posted by Pblais

Personally, I would add dual Racor 500 filters / separators and forget about fuel polishing totally.

Hey Paul, thanks for the feedback! We do have dual Racor 500's actually (setup in parallel, not series though). Good to know our current setup is solid.

I've heard so many bad things about Mexican fuel and enough stories about engines dieing 100 yards off the breakwater that I'm very protective about our fuel supply. Another reason I'm interested in this project is that we already have the fuel pump in place. The only new component we'd have to add is a T-valve and enough fuel line to tap into the fill or vent line to return the fuel back to the tank.

[Pblais]

I've heard so many bad things about Mexican fuel and enough stories about engines dieing 100 yards off the breakwater that I'm very protective about our fuel supply.

That was the guy we bought our boat from thought. He had was all over with it and never ran into any bad fuel, though I'm sure there could be some. The truth is the fuel is mostly fine. It's more a problem from sitting around and collecting water. If you have a decent set up like the racor 500 you are already catching water and crud and you still have a primary fuel filter on the engine. If you have a good filter you are going to catch what ever is in there when it goes through the filter.

There isn't anything bad about polishing but I really don't see it helping when all you have is less than 100 gallons. If you were polishing it should not be connected to the main fuel supply line. You want it as short a run as possible with as few fittings as you can in it's own closed loop. You don't polish using the same engine supply filters either.

[DeepFrz]

IMO, having experienced a clogged fuel line (not filter) in a seaway, a fuel polishing system is well worth the effort.

If you do go with fuel polishing, like Paul said, keep it separate from your engine supply. Run a pickup to very near the bottom (3/4") at the lowest spot in the tank and a return tube to near the bottom of the tank at the opposite end. For a 55 gal. tank you will want a pump that will circulate your complete tank in about an hour or less and a filter and fuel lines that can handle that flow rate. Put a timer in the cct. so that it will shut off automatically after circulating the fuel a few times and a vacuum guage on the suction side of the circuit.

It's true that your engine does return filtered fuel back to your tank but that is only when the engine is running. A fuel polishing system can be run at any time (if you have the power available).

I think for a small tank like yours it will only be financially worthwhile if you can do the work yourself. Be sure to use all fuel rated products. If you decide not to install a fuel polisher, then commit to inspecting and cleaning the tank on a regular basis. Hope this helps.

[westsail42]

Probably well known on this site, but...

http://www.ktisystems.com/

These guys have complete systems for this stuff. Not cheap. But if you already have the racors, you can buy just the fittings and manifolds and connect them to your existing filters.

[Extemporaneous]

The attached is what I came up with for my system. It normally runs through both filters (10micron, then 2micron), but either filter can be taken off line and be changed while the engine remains running. Also if my electric fuel pump bums out on my engine, the fuel polishing pump can run my engine. I have not actually tried it yet, but as I type it is sitting on my living room coffee table approximately 90% complete. I will most certainly let everyone know how it really works. It is larger than I had hoped it would be.
Oh well, I see clean fuel as critical and would do this even if it had to be larger.

Extemp.

[James S]

Originally Posted by Extemporaneous

The attached is what I came up with for my system. It normally runs through both filters (10micron, then 2micron), but either filter can be taken off line and be changed while the engine remains running. Also if my electric fuel pump bums out on my engine, the fuel polishing pump can run my engine. I have not actually tried it yet, but as I type it is sitting on my living room coffee table approximately 90% complete. I will most certainly let everyone know how it really works. It is larger than I had hoped it would be.
Oh well, I see clean fuel as critical and would do this even if it had to be larger.

Extemp.

My hats off to you for "going for it" but I count 9 three way valves in that system.
Will you be able to come up with a reasonable set of instructions for others that may have to operate this in a pinch?

The reason I ask is I went through a lot of work trying to optimize a drain system on my boat....only to end up with something that required an operators manual to drain the sink...OK, I'm exaggerating!
Fortunately I had my buddy do a review of my plans before I actually did anything on the boat.

[JamuJoe]

I have the diesel microbe plague. Thankfully it only seems to be affecting one of the 45 gal tanks on my Leopard 42 Catamaran. I have dual Yanmar 3JH4E's and no day tanks, simply one tank per engine. I'm cruising in Honduras and have been in a frustrating cycle of clearing the sludge from the pickup line, changing the Racor filter, bleeding the system etc.. I've drained gallons from the tank bottom (the tank has a bottom drain valve) until I have clear diesel. Each time it seems like I have it sorted out, the engine will run for hours at anchor, and then I leave the harbor and hit wave action and the engine dies within 30 minutes. The original incident occurred while motor sailing in heavy seas with the tank approaching 1/4 full. Unfortunately, after thinking that I had it sorted out, I took on fuel in Utila, and now have 45 gal in this tank. When the problem recurred during the passage from Utila to Roatan, we opted to sail to La Ceiba where hopefully I can get some biocide and replacement filters and can cobble together some sort of polishing system.

I've noted the opinions and advice regarding biocides and fuel polishing systems, but for now I must get this system clean and running again. Any and all advice for an 'on the water solution' will be appreciated.

[James S]

Do you have inspection ports on the tanks?

Are there baffles inside the tanks that may be holding back or trapping debris each time you drain?

We have used biocides with great success....we also fill with a baha filter.

Have you considered installing a vacuum gauge at or downstream from your filters...this my give a bit of a heads up, and a chance to switch-over filters before the engine stops.

[DeepFrz]

JamuJoe; You have to get the fuel out of your tank and filtered. Then scrub the tank clean. There are commercial businesses that will do that for you but they are not cheap. Then you can get the clean fuel back in. A good fuel polishing system will help you keep it clean. Keep it separate from your engine fuel supply.

You can check if you have a biological problem by taking a bit of the gunk from the tank and putting a few drops of ordinary household bleach on it. If it goes white it is biological, if it stays black it is precipitates from the diesel that have accumulated in the tank.

[Extemporaneous]

Originally Posted by James S

My hats off to you for "going for it" but I count 9 three way valves in that system.
Will you be able to come up with a reasonable set of instructions for others that may have to operate this in a pinch?

VERY VALID
I have thought of different ways of communicating the control actions and although I'm not 100% committed yet, I think it will have a color coded legend which will depict each of the different flow paths i.e. filters in series / filter # 1 offline / filter # 2 offline / polish only / or something like that. Once you decide what you want to do, you would follow the colored rings around the valves (the ring may have more then one color) which may for a particular sequence be blue and say 1 of 6, (go to the next valve) 2 of 6, and so on. A different flow circuit would be a different color and may not have 6 valve changes, and so it may be red and be 1 of 5, then you would go to 2 of 5 and so on. The to and from which tank will be separate instructions. I do believe that what I do come up with will either make or break this project. If not communicated simply and clearly it will be too complicated and even dangerous when trying to make changes in a pressure situation. I think I'll be able to come up with something acceptable.
What do you think?

Regards,
Extemp.

[Cheechako]

If your Caliber is not too old and if your filters dont accumulate much stuff, it might not be worth it. On the other hand I think it's a good thing to have. I had the fuel tanks "polished" on two older boats I bought and was amazed at how much stuff was taken out. I think I would have experienced what others have once out in rough water had I not had this done. I've heard that a Walbro Pump is the one to have.

[cat man do]

Has anyone used these yet as an alternative to Racor 500fg's?

eBay Motors: GTB228 EQUIVALENT TO RACOR 500FG FUEL WATER SEPARATOR (item 310122508046 end time Feb-23-09 03:58:41 PST)

I will need 4 so am looking at saving a few $$$

Dave