Fuel Filter Primer

[Stu Jackson]

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I agree with Noah that leaving the bleed screw open serves as a fuel polisher.  I don't do it on mine because I get a very small drip of fuel around the bleedscrew shaft when it is open... likely a bad seal.  I hope to replace the bleed valve (Kubota part?) at some point to allow me to operate as Noah does.

Dave, your M35 is self-bleeding, or should be.  Noah's M25XP has the choice of doing what he does or closing it.  One of Ron Hill's favorite topics.   

[KWKloeber]

Thanks stu.... now I get it.   also see note to Dave that's coming up.

#3 - there was a follow up, I'll resend.

Cheers
ken

[KWKloeber]

THANKS Dave, for the lead.  Yep, it sure looks like a DEEP rabbit hole.  But I get the idea now, actually it can all be somewhat simplified.  When I have time I'll take a schematic from an A-series/B-series engine and mark it up to post.

In return, here's the Kb part for the bleed valve....
Kubota p/n 14311-60504 -- about 20 bucks.  It may be that you can clean the shaft/tighten the packing nut (I think thar's packing under that thar nut??)



FWIW (forgive if you already know this -- others may not) the parts manual that TOAD has on it's website showing the setup for the M-25, XP, XPA IS NOT correct -- the electrical, etc., is NOT FOR THE A-series engines (the wiring is actually nearly identical to the B-series engines.)

On the bleed/polishing -- (let me take an alternate approach, not having read all the topics on this.)

Yes, keeping the bleed valve open will theoretically run more fuel thru the primary and on-engine filters.  I have no idea the amount (10% more, 50% more??)  But to what end? 

What that is, is not a "poor wo/man's fuel polishing system," it's a "clog up the filters that you depend on system."  I don't see a clear benefit to running more diesel thru the filters we depend on, rather than them filtering only the fuel the engine actually needs?  Is it better to catch crap sooner, i.e., before catching the same identical crap in the same identical filter(s) at some later point in time?  This goes to my (1) darned old "common sense" approach and (2) avoiding creating more unnecessary failure points.

I suppose an argument could be made that there's a benefit to getting crap out of the tank sooner rather than later, even if one needs to change filters more often (unless due to that the engine coughs while one is trying to navigate a breakwall in 40 kts w/ 6' following seas, in the dark)?  I (JTSO) think it's a weak argument -- and if being proactive re: the fuel quality is the goal, it's not THAT difficult to install another true polishing filter.

Cheers,
ken

[Ron Hill]

 Stu said -----  3. " Why bother?  With an M25 you should simply be able to run the fuel pump from the cockpit ignition switch.  For bleeding the secondary engine mounted filter I added a fuel pump shutoff switch as explained elsewhere.  Beats hustling up to the cockpit to turn it off when the fuel starts shooting out of the filter bracket nut on the secondary". 

Guys : You don't really need a separate switch, or running back up to the cockpit to turn OFF the key switch!!  Just turn off the battery switch and the 12V fuel pump stops pumping!!

A thought   

[Dave Spencer]

Ken,
Good point about "clogging up filters sooner than necessary".  I hadn't thought that point through.  Fortunately, we have good clean fuel at most places here on the Great Lakes as I'm sure is the case in most marinas on both coasts so the filters don't clog sooner than my replacement schedule.  This may not be the case in the Caribbean, Mexico or Latin America though so your point is very well taken.  Thanks for the tip on the bleed screw valve.  The minor drip isn't critical since it is cracked open so rarely but it's something I want to address eventually. 

Pic of M35AC bleed screw attached.  (Yep... the clamp is too big but it's what I had and hasn't leaked in 6+ years.  Another thing to get to... eventually )

[Ron Hill]

Dave : "Good point about "clogging up filters sooner than necessary".

Isn't that WHAT A FILTER IS FOR ????? 

My thought

[KWKloeber]

Pic of M35AC bleed screw attached.  (Yep... the clamp is too big but it's what I had and hasn't leaked in 6+ years.  Another thing to get to... eventually )

Yep, (sans clamp) looks exactly my M25 (the Kb ordered part) except of course I have the bronzy not "ice blue". 
No wait........ what's that extra injector doing on there???? 

Of course it's nearly impossible to find the correct mini clamps for those size lines (the banjo lines).  I ordered a box of them from Grainger 20 years ago.   Steve G also sells the no-cut ABA style here:
http://www.ultimategarage.com/shop/index.php?cPath=309_30&osCsid=de431u7gkp5inno8adrs87m3i2

kk

[KWKloeber]

Dave : "Good point about "clogging up filters sooner than necessary".

Isn't that WHAT A FILTER IS FOR ????? 

My thought

Yes, especially if Murphy intercedes and doing so causes the the engine to cough while one is trying to navigate a breakwall in 40 kts w/ 6' following seas, in the dark.   

Ron, I'm always eager to listen to fact-based arguments -- So...... what's the clear and convincing benefit of capturing the crap sooner, rather than some time later (as the engine uses the fuel)?

kk

[Stu Jackson]

Stu said -----  3. " Why bother?  ..............
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Guys : You don't need a separate switch, or running back up to the cockpit!!  Just turn off the battery switch and the fuel pump stops pumping

Ron, thanks for reminding us about that.  I keep forgetting it, and had actually installed that shutoff toggle switch a hands-width away from the secondary filter, so I could hold onto the socket ratchet or screwdriver and turn the pump off while still holding the screw, and then tighten it.  One Step Less. 

You boat, your choice. 

[Ron Hill]

Ken : With that kind of thinking on " Clogging up a filter sooner than later", I'm glad that you don't pack my parachute!!

My thought

[KWKloeber]

Ken : With that kind of thinking on "How to save the fuel filter", I'm glad that you don't pack my parachute!!

My thought

Yeah what I kinda expected. 
Rather than ill-placed quips (I never said you need to save the filter), I said it was unnecessary.

How about it if you have one  -- what's a real, honest, fact-based, not opinion, benefit to filtering out the crap ahead of time, when the exact same filter will do the exact same thing, as the engine calls for fuel?  As I said, fact based -- it creates an unnecessary additional (although albeit small) chance of failure, which naturally (per Murphy) will occur at the most inconvenient and life threatening time.  If it was recommended to continually bypass, why did Kubota put a valve there?  Why not hard pipe it? Another thought too.

Ken

[britinusa]

Ok, another 'No Big Deal' operation.

I drained the fuel from the filter with a diaper below to catch any drips. Caught the drips and drainings in a plastic cup.

Unscrewed the filter bowl
Used a filter wrench to remove the filter from the housing.

Cleaned out the filter bowl, inserted new Bowl to Filter -O- ring and Filter to Housing ring.

Half filled the bowl with injector cleaner.

Put it all back together.

Ran the fuel pump (Ignition On)
.. Initially the pump was running very fast (not ticking, but racing)
.. After about a half minute, fuel started to flow into the filter bowl.
.. After about another half minute the pump returned to it's normal Click Click Click.

Started the engine, no problems.

Ran the engine at 3,000 (never had it that fast before, I normally don't exceed 2200 rpm)
Then back down to 1000 rpm and left it there for 5 minutes.

Worked like a charm.

Next, I need to clean the tank. Starting a new thread.

Thanks everyone for great advice.

My conclusion is that there is no need to prime the filter with my setup, just be patient for a minute.

Paul

[Ron Hill]

Paul : I found it easiest to take a coffee can, put it under the filter and bowl and take them off together.  just let them drop into the coffee can and the split the bowl from the filter on the dock.  Either clamp off the fuel line or shut the fuel off so it cannot syphon - because it will if the tank is near 1/2 full!!

Also I always assembled both together filled them full of injector cleaner and then screw the two back on.  Guess that knowing air can cause a problem is why I found it easy to fill them full - even though I know how the electric pump operates - but that's just me!!

Then run the engine for a few minutes.  easy task

[britinusa]

Thanks Ron.