Primary Fuel Filter change out

[Stu Jackson]

Paul, #12 makes no sense.  You don't need the coffee can to install the NEW filter on the housing.  Pour some injector cleaner in the filter, doesn't even have to be full, and screw the filter straight up into the housing, easy peasy.

We all recognize that the first time you do this dreaded task there is a tremendous amount of pressure 'cuz when I was there I kept saying to myself: "What if the engine never starts again?!?"

This is a case of where the dreaded event is so frickin' easy that once you do it you'll wonder what all the fuss was about.

That's why we wrote it up in such detail and said "Don't reinvent the wheel."

Good luck. 

[britinusa]

Stu, you pretty well nailed the apprehension! Eximius' Engine is the first Diesel that I have actually had to 'work' on. (I don't count the huge diesel engines in the Air Base Emergency Lighting Generators - I just had to know how to start them up!)


List updated.

[Ron Hill]

Paul : Your M25XP engine is a tough critter, made to be working on a tractor in a very dirty environment. 

So don't baby it.  Just make sure it has clean fuel. 
You might want to leave the bleed valve open 1/4 turn and have a "self bleeding" fuel system.

A few thoughts

[KWKloeber]

Thanks guys.

I do not understand how the air is bled from the filter without cracking the bleed screw on the top of the filter, although in my mind, cracking the bleed screw on the injector pump while the electric fuel pump is running (clicking) could bleed the air from the lines all the way to the injector pump input.

One of the videos that I saw (Kabota Engines) described cracking each of the injector nuts on top of the engine and bleeding each line from there. In that instance, they suggested pulling the decompression lever to make it easy to turn over the engine. I figured that if that had to be done, then I should also close the engine raw water sea cock to prevent flooding the muffler. Raising the decompression level would also prevent the engine from starting (important as the sea cock would be closed).

FYI, I have not yet got my eyes on the injector pump bleed screw, so I don't know if it has the bleed valve mod or is still just a bleed screw.

Paul,

As far as WHY- think of it as if the city works on water lines or you do work on a well and air gets into the pipes.  You don't open a vent away from the end point of the line you want to bleed.   You open the vent at the last point in the system to get out (all) the air.   The lift pump fills the line with fuel -- the fuel displaces the air and moves it to the return line (in my case out the nib of my bleed valve.)

Some more history  -- the M-25XP engines have a bleed knob, the M-25 engines have a bleed "screw" (actually a hex-head bolt w/ metric machine screw threads) --- they both serve the same porpoise -- bleed air just before the injector pump. 

The M-25s just bleeds air/fuel out to the atmosphere through the hollow hex head -- or all over the engine as it were [I used to catch it with a solo cup.]  The fuel return line comes off the front of the engine (actually from the banjo on injector for the #1 cylinder.)

The XP engines bleed fuel/air into the return line to the tank (which many simply keep it cracked to fully open all the time to leave a continuous flow of fuel return to the tank [i.e., polishing].)  The bleed line goes to the banjo on the injector for the #1 cylinder -- the fuel return to the tank comes off the rear of the engine (actually the banjo on the #3 cylinder.)

I upgraded my M-25 hex-head bleed to the knob type for convenience, but DID NOT plumb the bleed back to the return line -- w why?  So I know when she's pushing air and when not, and to see the fuel (as I covered previously.)

The B series engines (M-25XPB or M35B) are "self bleeding" -- the fuel is continuously bled from a banjo on the injector pump to the #1 injector banjo.   If the B-series engine do need additional bleeding, you loosen an injector compression nut(s) or there is actually an "unused" bleed screw (hex bolt) on the pump (same as the M-25 engines.)  So essentially what Kubota did was to fully open up the bleed circuit (which as I said above some XP owners do by leaving the bleed know open.)

Happy Near Year,

kk

[Stu Jackson]

Thanks guys.

I do not understand how the air is bled from the filter without cracking the bleed screw on the top of the filter, although in my mind, cracking the bleed screw on the injector pump while the electric fuel pump is running (clicking) could bleed the air from the lines all the way to the injector pump input.

One of the videos that I saw (Kabota Engines) described cracking each of the injector nuts on top of the engine and bleeding each line from there. In that instance, they suggested pulling the decompression lever to make it easy to turn over the engine. I figured that if that had to be done, then I should also close the engine raw water sea cock to prevent flooding the muffler. Raising the decompression level would also prevent the engine from starting (important as the sea cock would be closed).

FYI, I have not yet got my eyes on the injector pump bleed screw, so I don't know if it has the bleed valve mod or is still just a bleed screw.

Paul,

hreads) --- they both serve the same porpoise -- bleed air just before the injector pump. 

The M-25s just bleeds air/fuel out to the atmosphere through the hollow hex head -- or all over the engine as it were [I used to catch it with a solo cup.]  The fuel return line comes off the front of the engine (actually from the banjo on injector for the #1 cylinder.)

Good advice here except for this, because my M25 does NOT bleed fuel "...all over the engine..."

By opening the knurled knob, as discussed in the Bleeding 101 Topic, the fuel and the air goes through the return line. 

In 17 years I have never had a drop of fuel spilled at my engine knob.

Ever.

[KWKloeber]

The M-25s just bleeds air/fuel out to the atmosphere through the hollow hex head -- or all over the engine as it were [I used to catch it with a solo cup.]  The fuel return line comes off the front of the engine (actually from the banjo on injector for the #1 cylinder.)

Good advice here except for this, because my M25 does NOT bleed fuel "...all over the engine..." By opening the knurled knob, as discussed in the Bleeding 101 Topic, the fuel and the air goes through the return line. In 17 years I have never had a drop of fuel spilled at my engine knob. Ever.

Stu,  You missed this part ....

through the hollow hex head -- or all over the engine as it were

The original M-25s have a hex bolt, not the knurled knob.  The bleed is a hollow bolt, with a hole thru one of the hex faces (same bleed type as on the B-Series (25xpb, 35B etc) engines (see pic below).  Loosen the bolt, and fuel moves through the bolt and sprays out the hole on the hex -- if you are quick you can position the hole "down" and catch it in a cup. If you have an M-25 with a knob, it's a late model -- I thought the knob was incorporated only on the Kubota D950 block (XP) production, not added to the D850/M-25, but I know there's other mods that were made to later D850 blocks. 

I ordered my knob assembly from a Kubota dealer and it screws right in place of the hex bolt assembly.

kk