Fuel filters for M25XP

[Stu Jackson]

While this is aninteresting subject, I wonder just how many of us, who regularly change the filters and inspect them (drain water, etc.) have had real engine problems BECAUSE OF the filter.  Not trying to rock the boat, but if indeed things are working well with the 2 micron Racor & water separator and the secondary on the engine, what's the basic problem?  Doesn't regular maintenance and inspection work to "nearly" eliminate engine failure because of the filters themselves (notwithstanding clean fuel habits, cleaning the tank, etc.)?

Stu

[reedbr]

Since the topic of engine filters came up, can I ask a question?  I have changed my Racor 2 micron filters twice now (each spring).  Despite some of the horror stories I found searching here, my Racor filter change has been so smooth I was worried mayhem was waiting until after I left the dock.  However, the engine has never even stumbled for a second after a filter change.  I didn't want to push my luck by changing the engine filter and Ron's posts gave me justification to ignore it.  So here's my question.  Is the process for changing the engine filter any different than changing the Racor?  I switch off the fuel line, place a catch rag under the filter, unscrew it, fill the new filter with fresh diesel, and screw it back on.  Turn the fuel line back on and run the engine for 1 hour and I'm done.  Is that the same process for the engine filter, or is there another bleeder valve?

[Stu Jackson]

Brain

In concept, you are exactly right.

In reality, the secondary fuel filter is a BEAR to access, and you may want to consider NOT filling it with fuel first because access is restricted and if you drop it, guess what.

There was a post on this a few months ago.  I'll try to find it for you later, but try a Find on Fuel Filters and scan through the list.  It talks about filter wrenches which would also be a good find topic.

Stu

[reedbr]

Engine Fuel Filter:

This is the engine fuel filter on my M35 in an MKII.  Access would be OK without the cables.  Maybe I'll take a whack at it later in the summer.

[Stu Jackson]

FUEL FILTER WRENCH

Brian

Here's the link to the filter wrench discussion:

http://c34.infopop.cc/eve/ubb.x?a=tpc&s=329609511&f=829605811&m=539108044&r=493109164#493109164

Nice picture.  How'd you get a camera in there?

That's where the secondary filters are on both the M25 and later engines.

Stu

[reedbr]

Stu-  That's the standard view from the aft cabin engine access door on a MKII.  I have digital pics of the Racor, stuffing box, and front of the engine too if anybody needs them for reference.

Ron-  I saw you restarted this post as another thread since this one was getting long.  However, I just have to say here that you can't con me to taking apart a perfectly running engine in the middle of a cruise!  Nice try.  I know stress is caused by working on a car at midnight that you need to drive to work at 6am...and yes, as always I learned it the hard way.  This seems to fit in the same category.  Thanks for the offer though.

[Stu Jackson]

Aw, gosh, it's only an engine bleeding

OR

a bleeding engine

:)

[Stu Jackson]

Most of the time it's FEAR (of bleeding).

It is NOT that hard.

It is SOOOO easy, it's silly.

Read this:

http://c34.infopop.cc/eve/ubb.x?a=search&s=329609511&reqWords=bleeding

[Mike and Theresa Vaccaro]

Interesting side note regarding fuel systems.  After yet another fouled filter this weekend, I finally pulled our tank for cleaning.  As Ron stated, it's really quite simple after the fuel has been pumped out.  The hardest part of the job was standing around whilst the electric fuel pump pumped the 20 gallons on-board into jerry cans.  You do have to rotate the tank slightly to get it through the aft cabin door ('88 Mark 1), but if only residual fuel is in it, it's possible to do this without spilling any fuel.  A couple of gallons of de-greaser and acetone took care of the 16 year-old biology experiment on the bottom of the tank.

Now the important part:  Of 12 small hose clamps on the primary fuel and fuel return lines, 6 broke off in my hand due to corrosion when I attempted to remove them.    These were the original factory clamps, near as I was able to ascertain, and most connections were double-clamped.  This is a classic case of a "stainless" hose clamp with a non-stainless screw.  Both the main fuel pickup and fuel return line at the tank HAD NO FUNCTIONING CLAMPS holding the lines in place.  Certainly a potential source of air in the system--not to mention the hazard associated with a failed fuel line.  Interestingly, a simple visual inspection of the clamps did show evidence of corrosion, but not until you put a screwdriver or socket head on the clamp can you be sure if it's properly secured or not.  Any clamp, showing any evidence of corrosion merits attention!

We are replacing all of the fuel line as a precaution as well as all of the hose clamps in the system.  We are also replacing the spin on Racor primary with a 500-series filter.  This is do to a couple of bad seals that I found during disassembly.  Note that Racor does make a seal kit for our old filter, and it is repairable--we just want to transition to more inexpensive drop-in type filters and are willing to pay a few extra bucks for the filter.

Cheers,

Mike