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Discussion Starter #1
My boat came with an old Fram fuel filter that has a cartridge inside but it does not have a viewing window to see the water/fuel that has been separated. So I modified the drain fitting on the bottom with clear tubing and a valve. This way I can see when the water has been drained out of the filter and it is only diesel remaining...



What do you guys think? Will the vinyl tubing hold up to diesel fuel? Or should I use the cloudier Polyethylene tubing?

I just don't want to spend the $$$ on a Racor unit just yet until I fix some other things. I do like the idea of being able to see the liquid being drained though.

Zac
 

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It looks suitable to me. I have this same Tygon tubing used for my pneumatic bilge pump that has had an exposure to diesel fuel at a time without any sign of deterioration. If you check the Tygon tubing commercial site you will see that they have a tubing with a yellow color, but still translucent, that is suggested for fuel.
 

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One of None
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you can get a fuel bowl at a tractor supply I think.. pretty cheap too.. just put it in line.
around 12 bucks
 

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Vinyl is incompatible with diesel fuel ... Long term soak will promote 'softening'. Suggest you change the sight tube to Tygon polyethylene or a 'teflonic'.
 

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Additionally, I doubt the water will make it down the tube; the opening is too small at the top without flow. Second, the needle valve will clog with dirt or even emulsion; a ball valve is needed. However, it is unsafe to use a ball valve as the sole restraint on a drain; it is far to easy to bump the valve open and slowly drain the whole tank into the bilge.

And, as Rich described, I have seen PVC fail with diesel many times.

Put it back the way it was. Better, just drain a few drops every time.
 

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One of None
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Or? this could be an odd thought... maybe clean the tank and don't let water in?
 

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pdq is quite correct.

YOU have modified your fuel delivery system. If you have a leak due to YOUR DESIGN which is not totally compliant to TODAYS current ABYC/USCG specs. and recommendations, your insurance carrier will probably not pay for any enviro-damage if this design causes an oil spill (just a sheen on the water!!!!). Sorry but in today's over-regulated, authoritarian and lawyer controlled world you really dont want to make yourself vulnerable by not strictly following 'the rules'.
At the least, Id recommend that you change out that filter to one of the USCG compliant, commercially available (Racor, etc.) filter sets with a 'see through' bottom sump with a direct-close drain valve. Your Fram set up is 'automotive' and is probably not currently USCG approved - Id recommend that you replace it.

Most important solution is find the reason for the water intrusion into the tank:
1. bad deck fill .... broken or worn O-ring.
2. Always topping off the tank tank, etc.
Best practice is to keep the MINIMUM amount of fuel needed plus some 'reserve'; ...... only buy your fuel from a 'high turnover' source such as a depot that caters to commercial fishermen/watermen/mega-yachts or jug it in from a busy 'truck stop' that caters to 18 wheelers - to keep the fuel 'fresh' and to have the least amount of water uptake from the atmosphere through the vent; ...... plus drain and empty the tank when not using the boat for long periods of time such as winter haul-outs, etc.

Here's an example of a Racor filter with a see-through sump and a 'water shedding' filter media (sorry for the listing of competitor but I didnt see one in the Sailnet 'store'):
http://www.westmarine.com/buy/racor...fuel-filter-water-separator--P006_180_003_550
http://www.westmarine.com/buy/racor...el-filters-water-separators--P006_180_003_507
 

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Or? this could be an odd thought... maybe clean the tank and don't let water in?
Great idea. Are you going to come over and help rip up the floors, cut access holes in all 4 baffled compartments, clean the tank and then rebuild everything?
Taking fuel in the third world, one gets a bit of dirt and water, now and then, so would you please explain how I can be sure I "don't let water in", without spending HOURS and HOURS at the fuel dock, checking each liter of fuel for water?
A good filter system is the best one can do in many cases, and suggesting ridiculously expensive or impossible things is not very productive.
 
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Discussion Starter #11
Thanks for the replies everyone. I will remove the vinyl and needle valve from the system and just find a wing nut plug to screw into the 1/8" NPT opening. The original drain was a hex head plug which is not going to be ideal for quick purging of the fuel. I was hoping for something that would be tool-less without having to purchase a whole new system. I just replaced the filter element in the Fram filter so I am going to run it this season and ask Santa Clause for a Racor unit.

On another note...
My Yanmar instruction manual says to keep the fuel tank 95% full and to top it off after each outing. I thought this was to keep as little humid air inside the tank as possible so it will not soak into the diesel.
RichH is saying to do the opposite. Can you explain the reasoning behind this?

Thanks again,
Zac
 

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The issue of water uptake from the atmosphere is simple, its called chemical equilibrium.

When diesel oil is processed the heat generated essentially dehydrates it and drives off all water. All tanks used to store it are vented to the atmosphere and the water vapor in the atmosphere eventually 'equilibrates' into the oil and eventually 'saturates' it to the maximum degree possible and according to the temperature of the oil being stored. A tank containing oil and vented to the atmosphere will 'lag' its changing temperature with the ambient atmosphere as the 'outside' temperature swings up and down; thus, will have continually different water saturation equilibrium and that equilibrium drive will eventually bring the oil to it maximum saturation with water .... until the temperature cools and some water separates, and drops to the bottom, the tank contents heats then cools and more water (as vapor) enters the oil to reestablish 'equilibrium' in the oil.

Empty tanks do not magically fill with water, do they? Yet partly filled or full oil tanks do accumulate water in their bottoms.

For 35 years, as a filtration engineer including deep involvement with ultra-pure chemicals, super high tech dielectric oils used in electrical transformers, etc. and if any container these are stored has any 'communication' to the wet atmosphere (vent), water will migrate into these chemicals and eventually saturate it ... sometime even through 'hermetically sealed' containers. Its just simple chemical equilibrium and ultimately the oil will saturate and with temperature swings and lags of the contents, water will separate fall to the bottom by gravity ... the tank and it contents now behaving like a chemical pump, continually extracting water vapor from the atmosphere and allowing to accumulate at the tank bottom.

In the oil industry, when oils are required to be nearly 'water free', we will constantly purge the tanks with bone-dry low pressure air or nitrogen or chemical foams containing nitrogen, etc. Even those million gallon storage tanks vented to the atmosphere will eventually become saturated with water if such steps to prevent migration of water from the atmosphere isnt taken.
Why I recommended the Racor 'water shedding' membrane systems is that it removes the 'free' or 'visible' water from the oil and you will then not 'slug' a hot fuel injector with relatively cold water thus potentially breaking the injector tips.
;-)
 

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either keep it full or really empty your choice...

Ive always had luck topping off my tanks when not in use...

but even when not I havent had bad water issues even with crappy third world fuel and diesel sitting for over a year in hot humid tropical climates...

a simple drain from the bowl before the season is enough in most cases and last but not least a stabilizer of your choice does help a bit too

my fave is seafoam
 
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