Fuel Filter

If I have a filter restriction indicator on my Racor filter (diesel) and it's not showing any restriction and there's no water when I drain the bowl, is there any good reason to replace the filter based on age or hours?

Ron

You will get answers all over the lot as to whether to replace the filters for age and not hours of use (one year is the frequently mentioned time). Couple of things to thing of:
the diesel and sludge in the bottom of the filter housing solidifies with time and needs to be drained - yearly would seem to work. The O-Ring on the top of the housing also solidifies and starts to leak with time (after exposure to diesel??) and will start to leak air into the fuel system. For years I have replaced my filters at the beginning of the season, the cost is not great and thus lessens the chance of a problem. If you allow the drain to be blocked by solidified junk and diesel it is a mess to take apart, at least on my boat.

rwidman said:

If I have a filter restriction indicator on my Racor filter (diesel) and it's not showing any restriction and there's no water when I drain the bowl, is there any good reason to replace the filter based on age or hours?

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On low rpm low hp engines sometimes the fuel flow is do small you might not see much of a change on the gauge even when the filters are dirty. So I would change them from time to time. Say at least once a year so. So you can check on there condition. Checking them from time to time might give you a better idea as to when to change them. And if you start seeing them clog up sooner you'll know you have a dirty fuel issue before it becomes a big problem.

I think those vac gauges can be a waste of time and money on some engines. Better off spending the money on the water probes and alarms in my opinion.

I read somplace, I think it was on the Racor site, that after about 1 year they start to lose the ability to separate water.

I do the same as Marty, change mine every spring. I do both, Racors and secondaries. This way I know that my fuel system is ready for new season. A full set of spares is always on board, just in case.

jleonard said:

I read somplace, I think it was on the Racor site, that after about 1 year they start to lose the ability to separate water.

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That is what I was told as well, whatever the filter elements are coated with will lose it's ability to repel water and it will saturate the element. Hence the recommendation to replace the Racor's annually.

I was also told the vacuum gauge is only valuable when you read the pressure at full throttle. At typical trawler speeds, the fuel demand is very low.

Racors when aged lose their seal around the stem in the pot. Allows dirt to bypass. If you lift the element out and there is no drag, then it was in there too long. Most are fine at a year. I change mine once a year. That's probably a good interval.

I would replace at least once a year regarless. Better to replace while tied up, than trying to replace while you are drifting toward a rocky shore...

I hate to be the guy who posts a question and then posts his own answer, but I got out my paperwork ( I have the kind that has a metal filter that screws on and a plastic bowl that screws on to the bottom of the filter) and to quote Racor:
"Frequency of element replacement is determined by fuel contamination level. Replace the elements every 10,000 miles, 500 hours, every other oil change or at the first indication of power loss, whichever comes first."

My restriction indicator is not a gauge, it is a plunger that remains at the highest vacuum until reset. I don't have to look at it with the engine running under load.

The other thing is, I have two filters installed at all times with a lever to change from one to the other. The "spare" filter will sit with fuel in it for a long time while the other filter is in use.

Since my 2 micron Racors usually need changing about every 75 hours or so, I had not given much thought to this issue. However, the efficiency of the filter to accumulate "dirt" actually improves as it gains a layer of "dirt" on the filter substrate until it reaches the point of blockage or inadequate flow, usually recognizable as vacuum pressure (engine sucking) or engine rough running.
I doubt that the filter loses its ability to separate water, but it is possible, and probably a question better answered by the manufacturer. We typically find that even with "clean" fuel the 2 micron filters need changing in less than 100 hours running our 280 Cummins at trawler speed, and are set up with duplex filters for easy switch over. I have never found any water in the Racors in 8 years.

Wow...went 400 hrs last winter on my 2 micron racor and it was spotless when I took it out to inspect....at 1.9 gallons per hr...that's not much fuel through it so I'm not surprised.

What kind of gallons do you think you put through them to require changing between 75-100 hours...if it's less than 1000 gallons..I don't think you have clean fuel.

I may be wrong here but I look in the bowl. It gets a new filter when I can see spooge in there.

I also understand the water separation function is conducted by the 'turbine' part of the filter structure, it's supposed to spin out the water if there is sufficient flow to actually spin. Why buying too large a filter defeats the water-spinning process, yet I have 1000s which are probably too large but the filter element is much larger than the 500 or 900s.

You are saying the filter itself acts like Gore-text to filter out the water?

Xsbank said:

I may be wrong here but I look in the bowl. It gets a new filter when I can see spooge in there.

I also understand the water separation function is conducted by the 'turbine' part of the filter structure, it's supposed to spin out the water if there is sufficient flow to actually spin. Why buying too large a filter defeats the water-spinning process, yet I have 1000s which are probably too large but the filter element is much larger than the 500 or 900s.

You are saying the filter itself acts like Gore-text to filter out the water?

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Yes the filter element itself does a lot, if not in some cases all, of the filtering out of the water. Many engines do not flow enough fuel to create much if any "turbine" action in the filter body.

Racor will tell you the same thing.

That is why I'd rather have the larger element units. So I have lots of surface area to maximize time between element changes.

http://www.parker.com/portal/site/P...BINE+SERIES+FUEL+FILTER/WATER+SEPARATORS&Wtky=

Stage One: Separation
As fuel enters the filter assembly, it moves through the centrifuge and spins off large solids and water droplets which fall to the bottom of the collection bowl.
Stage Two: Coalescing
Small water droplets bead-up on the surface of the conical baffle and cartridge element. When heavy enough, they too fall to the bottom of the bowl.
Stage Three: Filtration
Proprietary Aquabloc®II cartridge elements repel water and remove contaminants from fuel down to two micron (nominal). They are waterproof and effective longer then water absorbing elements.

psneeld said:

....at 1.9 gallons per hr...that's not much fuel through it so I'm not surprised............

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We may actually burn 1.9 gallons per hour but more than that is passing through the filter and then back through the return line. I have no idea how much but there is some.

rwidman said:

We may actually burn 1.9 gallons per hour but more than that is passing through the filter and then back through the return line. I have no idea how much but there is some.

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Mine is barely a couple ounces an hour depending on RPM...I have measured it.

I would hope anyone familiar with their fuel system would know what their engine returns.

This was my question to him..."What kind of gallons do you think you put through them to require changing between 75-100 hours?"

Notice how I didn't say "how much do you burn an hour?"

psneeld said:

I would hope anyone familiar with their fuel system would know what their engine returns.

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I consider myself familiar with my fuel system, especially after the issues I had with the failed fuel cap and water contamination a year ago. But I never thought I had to measure the amount of return fuel to be REALLY be considered 'familiar' with it. Has anyone else who's familiar with their fuel system also measured their return fuel rate or am I the only one?

Just when you think you've got a handle on it, something like this comes along! I guess I better raise the bar a bit higher.

It is my understanding that a typical 50 hours of run time on the 5.9 6BTA Cummins (280HP) equates to approx. 125 gallons consumed but as much as 1,500 to 2,000 gallons of fuel filtered. There is a high fuel return rate on these engines. So, 50-75 hours on a Racor 2 micron (not 10 micron) means the fuel is pretty bloody clean!!!

psneeld said:

Mine is barely a couple ounces an hour depending on RPM...I have measured it.

I would hope anyone familiar with their fuel system would know what their engine returns.

This was my question to him..."What kind of gallons do you think you put through them to require changing between 75-100 hours?"

Notice how I didn't say "how much do you burn an hour?"

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A quick look and it seems that diesel fuel return is all over the map, for example:
"Yanmar GM - just a dribble"
"Yanmar JH - half the fuel consumption"
"Yanmar LH - 60 gallons per hour"
"Detroit 71 Series - 80-90 gallons per hour"
And that was just the first four I found in some old manuals.

It is completely engine-specific, and I would imagine can be found in the owner's or service manual for each engine type. I even found reference to using the fuel return to transfer fuel between tanks, so you can be sure some engines return a lot.

The fuel return certainly does figure in the total fuel flow through the filter though.

Like they always tell me . . . RTFM!

Larry
M/V Boomarang

Chrisjs said:

It is my understanding that a typical 50 hours of run time on the 5.9 6BTA Cummins (280HP) equates to approx. 125 gallons consumed but as much as 1,500 to 2,000 gallons of fuel filtered. There is a high fuel return rate on these engines. So, 50-75 hours on a Racor 2 micron (not 10 micron) means the fuel is pretty bloody clean!!!

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https://marine.cummins.com/attachments/public/marine/Products/Auxiliary%20Engines/6b/fr90437.pdf

according to this...26 gal/hr returned at rated power (I think I read it right)

even so...a couple thousand gallons of fuel has never come close to plugging my Racor 500 2 micron...even when it's black there's virtually no restriction and probably could go for another couple thousand gallons.

I've run many deliveries and thousands of hours on commercial boats and never changed a filter in that amount of time even with pretty nasty fuel from all kinds of sources.

If some one is only getting 50 hours of use on a Racor element then they need to go up at least one size on the filter unit. As well as take a very close look at the cleanliness of their fuel.

With the proper size filters and clean fuel, you should get at least a hundred hours on a filter element no matter how much fuel your engine uses and returns.

I'm over 1,000 gallons in the past 12 months with just a fine sheeen on the bottom of my Racor 500. No water showing.

psneeld said:

..................... I would hope anyone familiar with their fuel system would know what their engine returns........

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I think it depends on the engine, not the fuel system.

It's not something I've ever been concerned with but I suppose I could find out if I really wanted to. As long as there's enough fuel pumped to satisfy the engine, I'm happy.

FlyWright said:

I consider myself familiar with my fuel system, especially after the issues I had with the failed fuel cap and water contamination a year ago. But I never thought I had to measure the amount of return fuel to be REALLY be considered 'familiar' with it. Has anyone else who's familiar with their fuel system also measured their return fuel rate or am I the only one?

Just when you think you've got a handle on it, something like this comes along! I guess I better raise the bar a bit higher.

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Al perhaps I missed it how many gallons an hour do your Perkins 4-236 motors return (each) to the fuel tank?
Thanks,
Bill

After all the comments about short run hours, I pulled out my log book today and checked filter change intervals. A number of different scenarios came to light!! There were some proactive change-outs before longer voyages to avoid the need to change underway - better to be prepared!! There were change outs after our tanks were cleaned when we first bought the boat. There were change outs with new fuel and most recently change outs with aging fuel. Hours run between filters varied significantly. Initially with clean tanks and fresh (road tanker) fuel we were getting 75-100hrs. Then for a period with barge fuel (fishing fleet and Ft. Lauderdale barges) we were were averaging more like 60+hrs. But we were also getting spikes up to 90hrs. Most recently (past 3 years) averages are running higher and as high as 150-200+ hrs with older fuel. My non-scientific conclusion is that there is a lot of variation between dirt handling capabilities of the 2 micron Racor 900 filters. I did drain tanks a couple of years ago and did not get any sediment or black particles in the final dregs.

I did also confirm that the Cummins 5.9 6BTA pump spec is 29GPH, so, for example, 100hrs of run time equals almost 3,000 gallons filtered.

Can't explain the lower numbers. If it was dirty fuel, then we cleaned it up just fine, because everything runs great!! I also think that there are most likely "tight" Racors and "loose" Racors. These are not precision items. I do know something about filters - I worked for a precision filter company selling ultrafine filtration to the pharma and electronics industries.
Last comment is that I do not really care whether I get 50 or 250 hrs provided the filters do their job and the Cummins is happy!! Plus I also have an on engine 2-micron filter after the Racors - belt, suspenders and jock strap!!.

I think that if you change your fuel filters before anything is showing in the bowl, or if your vacuum gauge is not registering, you are wasting your money and needlessly enriching Parker-Hannifin. I run a pair of filters for the 6CTA and can switch over with a simple lever to an unused filter if one gets gummed up.

Having said that, change your filters every day if it makes you feel happy (isn't there a song about that?)

I also have an engine mounted filter. I thought all engines did.

My Racor filters are 2 micron and so is the one on the engine. I know that doesn't make a lot of sense but it was like that when I bought the boat and I didn't see a reason to change what seems to be working.

I imagine if I was in a part of the world where dirty fuel was common I might use a 10 or 20 micron filter before the engine filter.

rwidman said:

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My Racor filters are 2 micron and so is the one on the engine. I know that doesn't make a lot of sense but it was like that when I bought the boat and I didn't see a reason to change what seems to be working.
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Same here. I change the Racor 500 filters when the need arrives (not enough flow to reach maximum speed), and change the on-engine filters during annual engine maintenance. Surely not efficient, but it works for me. Regardless, it's the cheapest part of boat maintenance.

Filters are cheap (depending on where you buy them) and being proactive sure beats trying to change over in the middle of the night 100 miles off shore in snotty weather!!