Fuel Polishing

[Swee Pea]

I have read the past threads on fuel polishing. I am putting one together to clean out my fuel tanks; I plan to draw fuel directly frm each tank, but I am a little "dense". Does the 12v fuel pump go before the separator and "push" fuel through it or does it go after the separator and "pull" fuel through it? Or does it matter?

Be kind.

Happy 4th of July!

John
SweePea

[Levitation]

Most people have the pump pull the fuel through the filter so the pump is handling clean fuel...
But in general, pumps push better than they suck...

If I were designing your recirculating design I would have a coarse screen and a water separator at the intake of the pump just to keep nasty stuff from passing through the pump and the high micron final filter on the out put side of the pump... No one else does it this way, that's just me...

Now, putting on my propeller beanie and wrapping my white scarf around my neck, I'm off!

denny-o

[Captains Cat]

[hardee]

Is fuel polishing a process for gas fuel as well as diesel? I didn't know it was done on gas. Would that take care of the fuel destabilization due to the ethanol content causing water absorbtion?

Harvey
SleepyC

[Swee Pea]

[AstoriaDave]

John,

No beanie and no propeller here, just a dumb chemist with test tubes in his ears!

I am curious how one might separate water from fuel that has absorbed more water because of the alcohol, except by repeatedly extracting it from the bowl of the fuel filter system as a separate layer. I've heard of folks rinsing the tank with pure alcohol (methanol or ethanol) to solublize any water layer left after the gasoline (etc.) has been pumped out, and then re-inserting fresh gasoline once the tank is free of water. Is that what you have in mind?

I don't think there is any practical, economical way to draw the water out if the gas/alcohol/water mixture is all one layer and the water has not layered out.

Am I missing something here?

[Doryman]

Hmmm. Your response, Dave, makes me beg the question: why not use a large filter (same principle as in-boat filter, on a larger scale).

Warren

[Swee Pea]

Beats me. I just read the posts and figured that the fuel separator separated the water from the fuel; the increased ethanol content attracting and holding water in suspension in the fuel. As the fuel is pumped from the tank and goes into the separator, the water/moisture is separated out and goes to the clear bowl where it is discarded. Recirculating the fuel several times may help reduce moisture content.

I am probably not following your question/response, but its the best explaination I've got. If Dr. Bob was on line, he would be able to explain better than I could.

Heck, I just wanted to know which side to put the pump on!

John
Swee Pea

[AstoriaDave]

John,

The separator/filter should accumulate water in the lower part, but if you have a lot of water, it might be several filters down the road before you get it clean. Try one for a couple gallons and see what is in the bowl. If no water, just keep going, until the filter quits working (assuming there is crud in the system) and renew. If the bowl fills with water, then likely the filter won't pass fuel very well, is my SWA guess.

It might be you need to make two passes on the fuel to get it free of water. Some fuel drier in the tank when you recharge it for the last time would help remove traces of water, also.

No matter how you slice it, the job is a PITA.

[Swee Pea]

Yep. Good suggestions.

John
Swee Pea

[BrentB]

I use a Mr Funnel when adding gas to remove debris but cant state how well it removes water
see
http://www.mrfunnel.com/Mr._Funnel/Models.html

I bought from Harbor Freight for $12

Be careful pumping gas, work in a well ventilated area and have safety items close by. Gas fires are very difficult to fight and 10 micron fuel and water filters (RACOR) are inexpensive
m2cw

[Chester]

Seperator filters with the clear bowl let you know what is in your system. One time when I siphoned the fuel out of my tanks I saw there was water entering the filter bowl from the bottom of the tank. I poured the water out of the bowl, poured some clean gas into the tank and siphoned the tank again. After doing this cycle three times I have never seen any more water in the fuel. I suspect it come in through the fuel vent.
You can siphon the tanks by removing the fuel line from the outboard engine, pushing a small sturdy piece of plastic into the end of the fuel line fitting to hold back the check ball and initating the siphon by squeezing the fuel bulb. Note, the check balls operate by gravity so pay attention how you hold the bulb.
This is a slow operation but it shows you can get the job done with just good filters.

[Levitation]

Ahhh jeeezzzz, someone has to be the prophet of doom here and no one else has stepped up to the plate - why does it always have to be me? (mumble, grumble)...

If you are polishing gas be daggone sure the pump you are using is sealed and rated for high flammables such as gas... Now, most pumps advertised for pumping diesel are likely safe, but with the proliferation of cheap imports/copies, you need to look closely... And be sure the switch or relay that controls the pump is either sealed or separated far, far away from the fumes, or both...

Well now, looky there - I got my nagging quota done for the month and it is only the 5th already....

[Swee Pea]

The pump I am using is a gasoline fuel transfer pump, specifically designed for pumping gasoline - got that covered. I bought a sealed in line on/off switch factory wired on a 10' wire and wired the pump with an insulated connector to the 10' wire. Got that covered. The only "violation" is the alligator type connector to the battery, which can spark. I figure the battery will be far enough away and polishing will occur in open air, not an enclosed environment.

Any other suggestions are always appreciated.

John
Swee Pea

[Larry H]

Here's the problem with trying to polish gasoline containing ethanol.

Gasoline and water don't mix. Pure gas (no ethanol) with water in it results in the water forming a layer under the gas. Filtering with a gas/water separator works fine.

Now when ethanol is added to the gas, it mixes totally, with no separate layers forming.

When water is added to the gas/ethanol mix, the ethanol mixes totally with the water, and with the gas, which results in one mixed fluid, with no layers. This fluid (water/ethanol/gas), will go right thru a filter/separator without removing the water.

If too much water gets in the gas/ethanol mix, the ethanol mixes with the water and the water/ethanol mix separates from the gas forming a layer of water/ethanol under the gas.

This is a very dangerous situation for the engine. If the fuel pickup sucks up this water/ethanol mix and sends it to the engine, the engine can suffer damage. Two stroke engines can be destroyed by burning water/ethanol. That mix removes the lube oil from the crank bearings/pistons/rings/cylinder walls and the low octane caused detonation. The same low octane/lean burn can also damage a 4-stroke engine.

So polishing gas/ethanol/water will only remove particles and crud, but will not extract the water from the mix.

Pumping a sample from the bottom of the tank and putting it into a clear container (glass-be careful) can show if there is any free water/ethanol under the gas mixture. If this is the case, I would empty the tank completely and start over with fresh gas with stabilizer added.

Since water and ethanol mix completely at any mix ratio, there is no easy way to remove the water from the ethanol.

This is why adding ethanol to gasoline is a bad idea for marine engines. Its not really a good idea for land vehicles either, but the fuel in a car/truck is used up more often and less problems result. However, if a car/truck/generator/mower/etc is stored, stabilizer should be added to the gas.