MK1 fuel pump wiring

[KWKloeber]

FWIW, it wouldn't start before I touched the fuel system.

Things to troubleshoot for
Is the IP receiving, good clean fuel; constant solid flow, not spurting air.

• If fuel flow is good, bleed the injectors.
• If the fuel flow is bad, is there a vacuum leak in the fuel train from the tank to the IP. Bleed at the IP.  Is the checkvalve in the primary filter ok?

[Stu Jackson]

FWIW, it wouldn't start before I touched the fuel system.

Things to troubleshoot for
Is the IP receiving, good clean fuel; constant solid flow, not spurting air.

• If fuel flow is good, bleed the injectors.
• If the fuel flow is bad, is there a vacuum leak in the fuel train from the tank to the IP. Bleed at the IP.  Is the checkvalve in the primary filter ok?

Add to those ^^^:  make sure the fuel pump is after the primary filter.  There is a small filter in the bottom of the canister fuel pumps and it should NOT be the first in line from the tank.

[Stu Jackson]

There's also this from the always helpful 101 Topics:

Bleeding 101    http://c34.org/bbs/index.php/topic,6377.0.html

There are lots of links in that topic and it would do you well to read them all, very worthwhile subject, especially for M25 and M25XP engines.

[Ron Hill]

Pete : All a diesel needs to run is clean Air and CLEAN FUEL !!  What did the bowl of the Racor filter look like when you change it? - I hope that you filled the new filter full of fuel before you screwed it back on?? 

Blead Blead Blead until you get clean fuel at the injection pump!!!

A few thoughts

[Ron Hill]

Pete : Are you using the M25XP bleed knob on the starboard side of the engine at the injection pump??

A thought

[Pete G]

Update:
The air bleed screw broke off immediately when I tried to open it.  I moved to the injectors, per the above recommendations and only had fuel flowing from from the first injector.  I verified flue flow to the overflow.  I next swapped the fuel filter, left it loose, and ran the pump until fuel spilled out.  I moved back to the injectors, but with the same result.  The fuel coming through is clean.  I plan on repeating the bleeding at the filter again and going back through the previous steps.  Suggestions welcome.

[Pete G]

New update. No change.

[waughoo]

Couple things come to mind... where are you checking for fuel at the injectors?  You say you're verifying fuel flow to the overflow.  Are you speaking of fuel at the return line to the tank?

If you crank over the engine, are you getting any signs of combustion?  If the system is bled to the bleed screw amd then on to the return line to the tank, I would think the next step would be to open the high pressure line at each injector and turn the engine over with the starter.  Repeat that for each injector and you should have enough fuel at the injectors to get it to start and clear the remaining small amounts of air.

This explanation though is offered with the caveat that I am not sure exactly what your process is to date.  The way you've written your process is a bit unclear for me to understand.

[Pete G]

I opened the high pressure lines and I'm getting no fuel to 2 of them.  I suspect a failure in the injection pump.  I could tell that the mechanic at the yard took a look - left the batteries to ALL and the keys in the ignition! Waiting for confirmation.  1 available on eBay.

[Pete G]

Reading in on the Kubota cross-reference, new at $699 vs $2200 for the marine version. Rebuild kit is about $30.

[waughoo]

I would consider rebuilding.  Mechanical injection pumps are well understood by diesel mechanics and are built in such a way that they can be refurbished.  It's at least worth looking into before going straight to a replacement.

[Ron Hill]

Pete : I hope that you went to the Kubota dealer and purchased /installed a new bleed valve?

Do you have a diesel truck engine repair company in town?

A few thoughts

[Pete G]

The bleeder valve seems specific to the marine version - $30 valve and $15 shipping.  Sign.  No readily available replacement injector pumps out there - everything is orderable but out of stock.  I pulled the trigger on a remanufactured unit and will rebuild the one I remove as a spare.  Pricey bleeder valve ordered, as well. 

[Ron Hill]

Pete : I wrote a Mainsheet tech note article on removing the M25XP injection pump and reinstalling it. I took it to a diesel truck engine shop and they rebuilt it. I listed the cost ?, but it was not exorbitant.

I can assure you that an extra injection pump is NOT on my spare parts inventory!!

A few thoughts

[Ron Hill]

Pete : BYW, with a different injection pump you are going to have to retime that engine!!  Good Luck!!

A thought