Fuel pump for fuel polishing system - Continuous duty pump necessary?

[Capn Jimbo]

Originally Posted by Pete7

I think that is a valid point, those who take the time maintain and do there own DIY polishing are also likely avoid a problem. Trouble is when you buy a secondhand boat you really don't know what is waiting in store for you.

How much is a professional clean? and how often do you do it, annually or say quarterly?

Pete

Pete here in Ft. Lauderdale - very boaty here - got my tank done by a professional who removes, pressure sprays, and repeat - nice job - for $160. I plan to repeat every 6 months FWIW.

[ATC]

Originally Posted by Kalimniosjohn

I can’t understand any argument against having an on board fuel polishing system. This forum is called cruisers forum....people are cruising on their boats, often to very remote destinations where good clean fuel just isn’t easily available. If you get fuel with particles big enough to see with the naked eye wouldn’t you like to be able to filter it before sending it to your primary fuel system?

I personally feel that the way I’ve built my system is pretty close to ideal. I can filter the fuel in my main tanks as many times as I wish. Then when satisfied, filter it once more and send it to my day tank. This way I know only clean fuel is being drawn through my engine fuel lines and filters which greatly reduces the chances of the engine stopping due to being starved by clogged filters. It just makes sense to me.

Polishing the fuel prior to being transferred to your day tank is great. Now any contamination that may cause immediate engine failure is remotely isolated to the day tank. This is idea for daily use but keep in mind a polishing system will not clean a fuel tank of the heavy sediments resting at the bottom of the tanks. Usually the cause of harmful contaminates is the HOT DIESEL being returned in to the tank. This causes condensation and that feeds the bugs.

[EmeraldCoastSailor]

This $50 auto parts store pump works for my DIY fuel polisher setup:
https://www.oreillyauto.com/detail/b...el+pump&pos=76

25 gph

Holley Electric Fuel Pump
Part # 12-426

[Nicholson58]

Roxy has a polisher consisting of a separate fuel dip tube added to a spare tank port. A Facet pump 45 gph. A Franz one micron filter. Gulf Coast Filter is an equal. The polished fuel returns to the tank by the regular fuel pick up normally feeding the dual Racors. In this way, loss of the polishing pump does not kill the fuel supply.

The Facet pump is a spring and solenoid operated reciprocating diaphragm pump. These are most often used as primary lift pumps on large diesel engines. Very reliable but I bought a spare.

I added this system after a failure of my HP injection pump due to silting by dirt. The polisher is so effective that I have not changed a Racor now for three years. I change my Franz element once annually. We live aboard In the Caribbean.

I also installed one micron Franz bypass oil filters on the main engine and generator, both diesel. I change the elements periodically but only change the oil when viscosity drops as indicated by oil pressure.

http://www.facet-purolator.com/tech-information/
Frantz Filters, LLC. Official Website
Gulf Coast Filters, Inc. Specializing in Bypass Oil filters, Fuel filters, Hydraulic filters and Custom filtering

[skipgundlach]

Originally Posted by EmeraldCoastSailor

This $50 auto parts store pump works for my DIY fuel polisher setup:
https://www.oreillyauto.com/detail/b...el+pump&pos=76

25 gph

Holley Electric Fuel Pump
Part # 12-426

This can also be used inline with a momentary push switch for priming in case of air gap when changing filters, or to assist in bleeding when the system is opened. I have one such, now dead, which I've toyed with replacing; this looks ideal to the purpose.

[Houssie]

Yes you need a continuous pump to successfully clean fuel otherwise it will burn out in no time at all.

http://allegrini.co.uk/wp-content/up...0108972350.jpg

and if your interested?

Fuel Polisher – Allegrini.co.uk – Sailing Around the world on our Beneteau Oceanis 473

[herbhunt]

I would suggest that you select a continuous duty pump and plumb it in so it can also be used as a replacement lift pump. To do this create a diversion valve from the additional filter you are installing so that the output can go to the engine. If you do this you can also use this pump to pressurize the fuel system when bleeding or filling filters etc.

[wingssail]

Originally Posted by TCL

As far as debate over whether a polishing system is necessary, I've enough anecdotal evidence to believe that the polisher will help. I scrubbed my tank clean in late fall, fuel sat in the refilled tank while the boat was on the hard over the Winter, and during a trip this Spring, with about half a tank, a night at anchor in some heavy seas apparently stirred up enough gunk to overcome the existing filtration.

Sorry, I just don't get the necessity of this system. We have two tanks, each with it's own Racor 500, and a manifold to select source and return. OK! the addition of a continuous duty pump would allow us to filter all the fuel from one tank through the Racor and into the other, then back, you have cycled it twice.

But in 38 years we've had this boat, and over 55,000 miles of cruising, all over the world, and filtering the diesel which comes in through nothing more than a Baja filter, we've only had a completely plugged filter one time, with black jelly like goop we picked up from a tanker truck in Nukalofa (that we failed to run through the Baja). That would have stopped up the polishing system immediately too. We change filters roughly once a year, usually when they start looking black, and honestly we just haven't had a problem. (we don't use biobor either).

I say, chill out and slow down on adding complexity to make a perfect boat and just keep it simple and use it more. The couple of days you'll spend on this polishing system could be spent sailing.

(A boat is not something you buy so you have a place to install all the other things you want to buy, but a lot of people treat it that way.)

[Beau.Vrolyk]

Can anyone give me a good reason to use a separate filter for polishing (other than the expense of the filter elements)? We have redundant filters (Racor 500) and we run everything (main engine, generator, polisher) through the same pair of filters. Zero problems for many years. Obviously, all Diesel engines (and many boilers) have a fuel return line which puts excess fuel back in the tank. This is effectively "polishing" the fuel.

Given the logistical hassles, carrying, mounting, and plumbing for a separate filter doesn't seem to make sense. The caveat is that we has dual filters which can be hot swapped anyway. I'm interested what rationale there is for a separate filter.

As to the original question, it's critical to measure the fuel flow in the polishing rig. It will be MUCH lower than rated no-head flow of the pump. In my experience, pulling through a filter, the flow rate is roughly 1/3 of what the pump is rated at; and this is with zero head. (pump is at the same altitude as the tank)

Finally, we have a sail boat with two tanks, one on each side quite a long way outboard. This allows us to use the fuel as ballast. The tanks are connected with a 2" pipe and valves to allow us to shift the fuel to leeward just before a tack, which we often do. In that 2" pipe we've installed a 10" deep trap with a drain. As the fuel flows from one tank to the other, it passes over the trap and heavy stuff (like dirt and water) falls into the bottom of the trap. Standard operating procedure is to drain this trap before starting the engine for along run. Back when the boat was new to us, we'd get a table spoon of water from the trap each time. Now, after new tanks, we don't get much but I like having the gross trap. it makes the Racor filters last longer.

BTW, there is a common misunderstanding about the source of water in the fuel. A friend and I worked to try and isolate the problem. We put a desiccant on the vent line to trap any water entering due to temperature changes in the fuel. We then hard-sealed the tank fill so that no water could enter there (after we filled the tank). Over numerous tank loads (dozens) there was no water captured by the desiccant.

We reversed the process, reconnecting the tank to the deck fill and leaving the desiccant in place. Water appeared. This was a very high quality deck fill with an o-ring seal. However, it was placed where standing water could sit on it while sailing upwind with a fair bit of heel. (San Francisco is almost always windy) We have repeated these tests on four boats with the same results.

The conclusion, after a lot of testing, is that the water isn't coming with the fuel here in the US. It isn't entering through the vent due to thermal changes in fuel temperature (at least not enough to find any in the bottoms of the filter bowls). It is coming through the deck fill either while sailing or (most often) while washing the boat.

[LargeMarge]

We had a similar discussion on SurvivalBoards:

The goal == a simple idjit-proof diesel transfer pump.

The process == developers cobbled a Fill-Rite 112C to a bicycle frame. A fan-belt provides energy transfer from operator to pump. (As usual, engineers saw multiple ways to complicate the design. Gear drive? Hydraulics?)

Filters == considerably larger than the 500 series. Apparently, the 900 series have significantly longer life, and reduce the effort at the pedals. This maintains a cool operator.

Changes == everybody agrees the plastic cups are fragile, so the metal bases won out for strength and longevity. To drain contamination such as water, plugs were replaced with bronze taps and hose.

Options == by counting the amount of fluid passing through the pump, the flow-meter (the 'C' designation after the '112') instantly shows the moment the tank contents are completely polished.

[LargeMarge]

Originally Posted by Maka

"Some in-line pumps models (Bosch P7100) return at least 40/50% of fuel to the tank, and Cummins PT returns over 80%."

Is the Bosch P7100 an injector pump? Different from a lift pump? Different from a transfer pump?

[Beau.Vrolyk]

Originally Posted by herbhunt

I would suggest that you select a continuous duty pump and plumb it in so it can also be used as a replacement lift pump. To do this create a diversion valve from the additional filter you are installing so that the output can go to the engine. If you do this you can also use this pump to pressurize the fuel system when bleeding or filling filters etc.

This is an excellent idea, if your engine is above your fuel tank. Aboard our boat, we're lucky enough to have the tank above the engine.

While you're plumbing things, one of the nice things to do be able to do while out cruising is give a little fuel to a friend who has run out. As a result, we have a "t" in our fuel polishing system that allows us to send filtered fuel out to a container or boat.

[wingssail]

Originally Posted by Beau.Vrolyk

Can anyone give me a good reason to use a separate filter for polishing (other than the expense of the filter elements)? We have redundant filters (Racor 500) and we run everything (main engine, generator, polisher) through the same pair of filters. Zero problems for many years. Obviously, all Diesel engines (and many boilers) have a fuel return line which puts excess fuel back in the tank. This is effectively "polishing" the fuel.

Given the logistical hassles, carrying, mounting, and plumbing for a separate filter doesn't seem to make sense. The caveat is that we has dual filters which can be hot swapped anyway. I'm interested what rationale there is for a separate filter.

As to the original question, it's critical to measure the fuel flow in the polishing rig. It will be MUCH lower than rated no-head flow of the pump. In my experience, pulling through a filter, the flow rate is roughly 1/3 of what the pump is rated at; and this is with zero head. (pump is at the same altitude as the tank)

Finally, we have a sail boat with two tanks, one on each side quite a long way outboard. This allows us to use the fuel as ballast. The tanks are connected with a 2" pipe and valves to allow us to shift the fuel to leeward just before a tack, which we often do. In that 2" pipe we've installed a 10" deep trap with a drain. As the fuel flows from one tank to the other, it passes over the trap and heavy stuff (like dirt and water) falls into the bottom of the trap. Standard operating procedure is to drain this trap before starting the engine for along run. Back when the boat was new to us, we'd get a table spoon of water from the trap each time. Now, after new tanks, we don't get much but I like having the gross trap. it makes the Racor filters last longer.

BTW, there is a common misunderstanding about the source of water in the fuel. A friend and I worked to try and isolate the problem. We put a desiccant on the vent line to trap any water entering due to temperature changes in the fuel. We then hard-sealed the tank fill so that no water could enter there (after we filled the tank). Over numerous tank loads (dozens) there was no water captured by the desiccant.

We reversed the process, reconnecting the tank to the deck fill and leaving the desiccant in place. Water appeared. This was a very high quality deck fill with an o-ring seal. However, it was placed where standing water could sit on it while sailing upwind with a fair bit of heel. (San Francisco is almost always windy) We have repeated these tests on four boats with the same results.

The conclusion, after a lot of testing, is that the water isn't coming with the fuel here in the US. It isn't entering through the vent due to thermal changes in fuel temperature (at least not enough to find any in the bottoms of the filter bowls). It is coming through the deck fill either while sailing or (most often) while washing the boat.

Absolutely great comment.

While a 2" cross system line might be overkill for most folks, questioning the need for a separate system is spot on. Our experience, with a similar two tank/two filter system, is similar. Many years, nearly zero problems.

[noelex 77]

Originally Posted by Beau.Vrolyk

Can anyone give me a good reason to use a separate filter for polishing (other than the expense of the filter elements)? We have redundant filters (Racor 500) and we run everything (main engine, generator, polisher) through the same pair of filters.

The polishing system will filter many hundreds of times the volume of fuel that the main engine primary filter will process. It will pick up the dirtier fuel at the bottom of the tank.

This is one of the advantages of polishing system. If the polishing filter is relatively clean there is little need to disturb the primary filter.

If the fuel is bad the polishing filter will clog very quickly. Therefore, it is not ideal to include this filter in the engine fuel system. A filter that is hot swappable does remove some of these concerns, but the ideal is to keep the polishing and fuel supply systems separate, especially as the pickups should be at a different level.

[Beau.Vrolyk]

Originally Posted by noelex 77

The polishing system will filter many hundreds of times the volume of fuel that the main engine primary filter will process. It will pick up the dirtier fuel at the bottom of the tank.

This is one of the advantages of polishing system. If the polishing filter is relatively clean there is little need to disturb the primary filter.

If the fuel is bad the polishing filter will clog very quickly. Therefore, it is not ideal to include this filter in the engine fuel system. A filter that is hot swappable does remove some of these concerns, but the ideal is to keep the polishing and fuel supply systems separate, especially as the pickups should be at a different level.

Having suffered through many different boats with many different fuel tank set ups. I believe quite strongly that the idea of having a pickup at different levels is a serious mistake. Therefore I have to respectfully disagree.

Here's why. The time when garbage in the fuel causes the most critical problem and could be threatening to the boat and crew, is in rough weather. In rough weather, the logic of having a higher pickup in the fuel tank fails. This is because the boat is moving around so much that all the fuel, and the garbage, is completely mixed. Having a higher and lower pickup only works when the boat is sitting relatively still and that is typically a time when the boat is not in any danger.

Before the era of effective, inexpensive, and reliable hot-swap fuel filters it mades some sense to have a higher pickup for fuel on the mistaken theory that you would avoid picking up the garbage in the bottom of the tank. But the experience of watching a semi-transparent water tank surge around (even with baffles) while being transported in a pickup truck made me realize that when it really counts, the difference in altitude between the pickups will not provide any real protection.

As a result, in fuel system I've designed over the last 20 years the bottom of the tank is never flat. It is sloped in both fore-n-aft and athwart ship to insure that any water or garbage that does get into the tank immediately enters the pipe leading to the gross trap and then to the filters.

The key point is that this garbage accumulates slowly and in small amounts. It's best to remove it immediately, especially before the water can encourage algae growth, rather than letting it build up. Before heading out, you really want to know that there isn't any garbage in your tank, rather than discover it once the boat has started moving and the fuel is surging around.

This is another reason we use the trap combined with the primary hot-swap filters, they are connected to the lowest point in the tank and are certain to eliminate the problem while it's small.

Finally, the Racor 75500MAX hot-swap filter is rated at 60 gallons/hour flow rate (when running only one of the two filters), we run the polishing at 50 gallons/hour to allow 10 for running the main engine and generator simultaneously; they only use 4 gallons/hour with both running full chat. There is plenty of excess capacity in the Racor 500, upon which the 75500MAX is built, to support all he polishing one wishes to do. For our fuel tanks, the polisher can turn over the entire tank in four hours, rate limited by the 50 gallon/hour rate of the Racor.