Fuel Filters

[Ken Juul]

Not to start another debate on the correct sized fuel filters, enough has been written on them.  But here is a different take on the issue.

At the Catalina Rendezvous we had a Yanmar rep speak.  He was very emphatic that the primary (Racor)must be no smaller than a 30 micron.  The reason being that the engine requires a lot of fuel for cooling/lubing the fuel system components, finer filters clog too quickly robbing the engine of the necessary fuel flow.  I only mention this for the owners of newer boats that may still have some time on the engine warrenty.  The engine will probably last for ever, but don't void your warrenty.

He also mentioned about 5 times to use a cetane booster and a lubricity enhancer with every fill up, they chemically mix with and become a part of the fuel.  The BioBor type products are also necessary, but do not chemically mix.  He said research has shown that most owners fill the tank up at about the half empty point.  If a full dose of Bio product is used, the concentration will eventually get too high.  He recommeneds adding the Bio product on every other or every third full up. The exception being if you suspect dirty fuel use it.  As has been mentioned on the board a couple of times, he recommeded "buy what the truckers buy".

[Jeff Kaplan]

ken, excellent post, that's what i've been saying all along. treat your fuel and if you fill via jerry jug, get the fuel at a truck stop...jeff

[Jon Schneider]

The BioBor type products are also necessary, but do not chemically mix.  He said research has shown that most owners fill the tank up at about the half empty point.  If a full dose of Bio product is used, the concentration will eventually get too high.  He recommeneds adding the Bio product on every other or every third full up.

Interesting.  I fill up every five gallons to keep the fuel topped off and because I prefer to do it by hand.  I actually only add the correct amount of biocides and cetane boosters for five gallons.  Every once in a while I double that amount, but I assume that the stuff stays with the fuel that's already there.

[Jeff Kaplan]

jon, your correct to add the right amount to the 5 gal., as the fuel in the tank is already treated. biospore or bioside, what ever a particular mfg. calls their product should be used in very small amounts and not with every fill. for us with short seasons, once in the spring will do for the season, but for you with longer seasons, maybe once a quarter add some, remember, this porduct is not a fuel cond. but rather designed to kill the cooties that grow in the tank...jeff

[Mike and Joanne Stimmler]

Is it save to "ASSUME" that since I have never had any water in my racor filter or had any clogging of the filter to cause problems with the engine, that my fuel tank is relitively clean. I have done sone extensive motoring in rough seas but have never had to put more than 5 gallons of fuel in. Would problems tend to show up more as the tank gets closer to empty? I do use a cetane booster and biobar as reccomended by Ron Hill  but have never had my tank out. Do I need to take it out and clean it just as a precaution?

Mike

[BillG]

Speaking from experience, I had my boat less than one season when I had filter clogging problems, the tank was almost full at the time and obviously it was some pretty big wave action that stirred up all the junk on the bottom. I have no idea what the  previous PO did or did not do with treating fuel. Once I realized what the problem was and changed out the filter, the new one only lasted several hours before it clogged up. The problem in removing and cleaning the tank was that it was completely full at the time, what a hassle.  The lesson learned is that a tank that is 20 years old probably needs to be cleaned and it is alot better to clean it on your schedule, like when the tank is almost empty, rather than once a problem occurs.

[Ron Hill]

Ken : I've heard all of the same things that you mentioned except the 30 micron!!  On that point I believe that the Yanmar rep was wrong.  Everything I've heard in the past 20 years has been don't go higher than 10/15 microns.  Before I believed that 30 micron statement I'd call Denso, Kiki and or Bosch (makers of injectors and injection pumps) and get the size that will "pass thru" and "not clog"!!

His point that fuel must flow thru the filter is well taken and that the finer 2 or 10 micron filters will clog faster is also true and must be changed more often--makes sense! 
But 30 micron filter size is bologna as far as I'm concerned.  After all we are only burning .5 (M25XP) to 1 (M35B) gph!!   
My thoughts

[Ken Juul]

Hi Ron, I'm with you on your line of thinking.  A 2 or 10 micron primary will ensure the harder to change engine mounted filter and injection system is not subjected to the fouling particles.  Keeping the bleed valve cracked a half turn or so will also increase flow through the system for cooling.  Just reporting what was said.

Yanmar owners, if your engine is still under warrenty, I'd check the fine and not so fine print in your owners manual.  It's still your choice on filter size, but make it an informed one.

[DaveM]

I have heard the following I grabed from a vendor site in more than one place over the years.

"Ultimately, the micron rating preferred will be a function of fuel quality, operating climates and maintenance schedules. Thirty-micron (PM) is recommended when the Turbine Series will function as water separator and primary filter. The ten-micron (TM) can be used for primary or secondary/final filtration depending on the engine and/or the application. The two-micron element (SM) is secondary/final filtration."

Apparently the 2 micon has a 2010S for secondary filter application and 10 micron is 2010T for transition when it is going between filters and the 30 micron allows enough flow to allow centrifugal effect for water separation.

Good Winds
DaveM
     

[Stu Jackson]

A cross reference for sizing filter designations is in Reply #7, here:  http://c34.org/bbs/index.php/topic,1124.0.html

If you do a search on "Racor" there is a lot of discussion of this subject.  That's ONLY for people who like to wade through old stuff , but that's how I found this link.  I have to amend "Your Boat, Your Choice" to "Your Boat, Your Computer and Your Eyes!" These discussions always turn up something new, so please keep 'em coming.  Plus it gives us an opportunity to help the new skippers out with information.

[David Sanner]

Interesting topic... I believe my spin on Racor is a 2 micron
and  my M25XP mounted is 10 Micron; a common config.

It's a nice configuration because assuming my Racor does
it's job I only change my engine filter ever 3 or 4 years or
maybe longer if I'm feeling lucky.  (Would it ever need
changing?)

I wonder what percent of the clogging material is below
2 micron and what is between 2-10 microns.

Are there any issues sending 2-10 micron particles
through the injectors?  If not why not just get a 10
micron Racor and minimize the likelihood of
plugging your filter or replacement schedule?

Or just leave working well alone and change my
filter every 100 hours or so?

If 10 micron is ok maybe a nice add-on would be a
bypass of my Racor?  That way if it plugs up I just
open a valve which routes around it, and the engine filter
does the job until I can safely replace the Racor.

[RV61]

Mike,
Per your question.

Would problems tend to show up more as the tank gets closer to empty? I do use a cetane booster and biobar as reccomended by Ron Hill  but have never had my tank out. Do I need to take it out and clean it just as a precaution.

I would not pull the tank and clean as a precaution unless I was finding anything in the bowl or in the bottom of the tank. As a precaution after a winter on the hard I pump some fuel out of the bottom of the tank and inspect the fuel  for  crud and water as this stuff tend to be at the bottom as diesel is lighter than water and the fuel pick up tube is picking up the fuel from the  bottom of the tank thus I think your assumptions are accurate.

[Stu Jackson]

Dave's bypass idea sounds like a light-bulb !!! going off over my head (or under my head sink!).  For years folks have discussed dual filters to be able to switch if one gets plugged up at the most inopportune times (ever found an opportune time for that to happen?).

Duh, keep forgetting the secondary filter ON the engine.

So, just put a bypass line in the fuel line around the primary Racor properly valved, keep running the engine while the fuel is bypassed, and replace the Racor.  Hmm, could save lotsa space and actually might work.

[Ron Hill]

RV61 : It's getting into rough WX that stirs up the fuel and all the other junk on the walls/bottom of the tank - that the problems show up, beside being below 1/4 tank full.   

David : Just remember that your Racor is also a water separator, besides being a filter!!

[Meerkata]

I am thinking of running a second primary Racor parallel to the existing one. I think I would get a Westmarine 500GSS2, plumb with a valve on either side and that way I can easily shift from one primary to the other, giving time to do a filter change. I understand that these filters are before the lift pump.
I am using 20 micron in the primary at this time.
All said, it still does not stop the secondary from clogging with 2 micron particles.
Jim