Is Fuel Polishing really necessary?

[sfellows]

I'm obsessed with having clean fuel in our diesel tank. Last week we had the primary Racor and secondary fuel filter elements replaced as part of a general Engine Service. Both were very clean in-spite of being in-situ for several years. The Racor had some water in it, but very little (I check this regularly).

We also had an intermittent fault with the fuel gauge, which meant removing the sender. With access to the tank and my obsession about clean fuel, we used a Pela-type pump attached to a straight probe to remove any water at the bottom of the tank (there was about 3L but this has never previously been done - around 10 years).

So why do we need fuel "polishing systems"? With a standard diesel engine setup and the return-pipe for un-used diesel fuel, the fuel s getting "polished" every time you use the engine. The only fuel that isn't polished is that used by the engine. As long as you can get any water out through accessing the bottom of the fuel tank I don't see any reason to "polish" the fuel.

Is it just another "fad" or have I got the wrong end of the stick?

 

[Refueler]

Now starts a long thread of Polishers !!

 

[[70521]]

Is it just another "fad" or have I got the wrong end of the stick?

If you ever experience the bug you will understand it is not a fad.

 

[Refueler]

If you ever experience the bug you will understand it is not a fad.

Fine ... but most setups I read about are not as good as the constructor believes ..........

 

[pcatterall]

If you are using your engine a lot and your engine returns a good amount then you may not need to use a polisher. If your fuel stands in the tank for long periods or you have got the dreaded bug then you will wish you had one.

 

[Bilgediver]

So why do we need fuel "polishing systems"? With a standard diesel engine setup and the return-pipe for un-used diesel fuel, the fuel s getting "polished" every time you use the engine. The only fuel that isn't polished is that used by the engine. As long as you can get any water out through accessing the bottom of the fuel tank I don't see any reason to "polish" the fuel.

Is it just another "fad" or have I got the wrong end of the stick?

Some engines only return the injector spill leakage which is minimal and other engines circulate more sometimes via an orifice restrictor near the injector pump . If you are definitely circulating large quantities then you are already polishing so just relax and enjoy the water you are floating on and forget your fuel tanks .

 

[geem]

Following the last fuel polishing thread, I checked how much fuel my electric pump was circulating. 500% of normal fuel use. A built in polisher!
I think the idea of filtering the fuel periodically to remove sediment and water from the bottom of the tank is a good one. I dont think a permanently installed system is a must. A simple Chinese copy Facet pump, a clear fuel filter and some clear pipe with a 1m length of copper twigging on the end and you can vacuum the bottom of the tank. It's a good barometer of fuel condition and peace of mind

 

[Plum]

I'm obsessed with having clean fuel in our diesel tank. Last week we had the primary Racor and secondary fuel filter elements replaced as part of a general Engine Service. Both were very clean in-spite of being in-situ for several years. The Racor had some water in it, but very little (I check this regularly).

We also had an intermittent fault with the fuel gauge, which meant removing the sender. With access to the tank and my obsession about clean fuel, we used a Pela-type pump attached to a straight probe to remove any water at the bottom of the tank (there was about 3L but this has never previously been done - around 10 years).

So why do we need fuel "polishing systems"? With a standard diesel engine setup and the return-pipe for un-used diesel fuel, the fuel s getting "polished" every time you use the engine. The only fuel that isn't polished is that used by the engine. As long as you can get any water out through accessing the bottom of the fuel tank I don't see any reason to "polish" the fuel.

Is it just another "fad" or have I got the wrong end of the stick?

With your current attention there is no need, in my experience. Remove your return line, put it in a measuring jug, run engine at cruising revs and measure/time how much is being "polished".

www.solocoastalsailing.co.uk

 

[Laysula]

As Geem says, It's the bottom of the tank that you need to get at. For the cost of a filter and pump, it gets rid of the crap and water that your pick up pipe doesn't reach. As you said you are getting occaisional bits of water in the filter bowl so there is probably a layer at the bottom of the tank.

 

[Bilgediver]

Following the last fuel polishing thread, I checked how much fuel my electric pump was circulating. 500% of normal fuel use. A built in polisher!
I think the idea of filtering the fuel periodically to remove sediment and water from the bottom of the tank is a good one. I dont think a permanently installed system is a must. A simple Chinese copy Facet pump, a clear fuel filter and some clear pipe with a 1m length of copper twigging on the end and you can vacuum the bottom of the tank. It's a good barometer of fuel condition and peace of mind

Beware. Most of the time the water sits on the bottom of the tank out of reach of the engine suction. It is not dispersed throughout the tank. To remove the water you need a separate suction to the bottom of the tank. the engine suction might gulp large quantities of water when the boat is pitching and rolling.

 

[geem]

Beware. Most of the time the water sits on the bottom of the tank out of reach of the engine suction. It is not dispersed throughout the tank. To remove the water you need a separate suction to the bottom of the tank. the engine suction might gulp large quantities of water when the boat is pitching and rolling.

I was suggesting using a separate electric pump to vacuum the bottom of the tank. I do mine annually. My tank has four pick up pipes. I have arranged the lowest one as the generator. Its right at the bottom of the tank. I use a high performance, high volume MANN filter on the generator. If I get a major problem the gen filter would block first.

 

[[2574]]

I was suggesting using a separate electric pump to vacuum the bottom of the tank. I do mine annually. My tank has four pick up pipes. I have arranged the lowest one as the generator. Its right at the bottom of the tank. I use a high performance, high volume MANN filter on the generator. If I get a major problem the gen filter would block first.

We’ve recently bought a boat that immediately prior to our ownership had a 4kw diesel genny professionally fitted, respected local firm did the job. Unbelievably no filtration was provided in the genny supply line. There’s a small inline disposable cartridge filter fitted in the genny unit itself but I thought it wholly inadequate. Now fitted a Racor filter/separator.

 

[geem]

We’ve recently bought a boat that immediately prior to our ownership had a 4kw diesel genny professionally fitted, respected local firm did the job. Unbelievably no filtration was provided in the genny supply line. There’s a small inline disposable cartridge filter fitted in the genny unit itself but I thought it wholly inadequate. Now fitted a Racor filter/separator.

That's terrible.
We use standard fuel filter spin on filter heads. You can buy them for little money off eBay. The sort of thing fitted to trucks and vans. Mine came off a Merc truck. It's a huge filter. It's all I have. I removed the paper filter unit off the generator engine. If the spin on filter is good enough for the Merc truck it's good enough for my little 450cc genny

 

[Graham376]

Following the last fuel polishing thread, I checked how much fuel my electric pump was circulating. 500% of normal fuel use. A built in polisher!
I think the idea of filtering the fuel periodically to remove sediment and water from the bottom of the tank is a good one. I dont think a permanently installed system is a must. A simple Chinese copy Facet pump, a clear fuel filter and some clear pipe with a 1m length of copper twigging on the end and you can vacuum the bottom of the tank. It's a good barometer of fuel condition and peace of mind

We have Facit on the engine and, as you say, it returns far more than is used. For checking the bottom of the tank, I used one of the cheap drill mounted impeller pumps as it takes a larger bore hose which is less likely to block. Took the Eber stand pipe out and fed fairly stiff hose through the hole and pumped into a couple of clear 5L water bottles.

 

[geem]

We have Facit on the engine and, as you say, it returns far more than is used. For checking the bottom of the tank, I used one of the cheap drill mounted impeller pumps as it takes a larger bore hose which is less likely to block. Took the Eber stand pipe out and fed fairly stiff hose through the hole and pumped into a couple of clear 5L water bottles.

I simply return my clean fuel directly back in to the tank. I ran the first bit in to a plastic bottle just to check for water but on finding none I just returned the filtered fuel directly

 

[Roberto]

FWIW, I have a large inspection opening in the tank and I use my home made filtering system once or twice a year (basically an intake metal tube fitted to a hose, cav filter, electric pump, return to tank). The "one" time the engine was stopped by fuel starving there was a sort of jelly ameoeba-like matter which was stuck against the tank outlet, no way to get rid of that without opening the tank. Actually, that thing had formed and accumulated inside the internal surface of the filling hose.
In a number of occasions an engine failure would have meant losing the boat, if not worse, so I would not be without that system.

 

[goeasy123]

This guy as an interesting angle...

 

[thinwater]

Of the people with polishing systems, which of you use a preventative dose of biocide?

As for the impossibility of cleaning a baffled tank... that's just not true. It may require an access hole or using a pressure washer with a flex lance, but it is possible. Anything else will leave stuff that can get stirred up.

Which returns us to the importance of prevention. Keep the tank dry. Sump the bottom annually (an oil change pump works fine). Use a biocide. A silica gel vent filter will prevent absorption. And run through the fuel at least annually.

 

[goeasy123]

I don't get polishing. Most engines recirculate fuel anyway. If you're looking to spend money on a solution that solves the problem of fuel induced engine failure are you not better of having a parallel filter system with a switchover when one circuit gets blocked?

 

[burgundyben]

My take on it is that the polishing rig won't pick up all the crud from the bottom of the tank. You'd have to give the tank a mighty shake then filter it fast before the crud settles.

In my opinion there is no substitute for once every 5 years draining the tank and scrubbing the inside, then mopping up and re filling with filtered treated fuel.