2007 Jinma 354 -- Leaky fuel supply hose -- questions!

[jonasthaler]

My Jinma 2007 354 has run reliably and strongly for years now, and I just used it about ten days ago to clean up our dirt road after a rainstorm.

Today it turned over perfectly but there was absolutely no ignition.

Upon further inspection, I noticed that when the engine was turning over (but not starting) diesel fuel was squirting, or rather seeping, out of the top ferrule (below the banjo fitting) of one of the fuel supply lines going from the filter to the injection pump. (See picture)

It appears that that fuel hose (with banjo fittings on both ends) needs replacing.

QUESTIONS:

1. Does the fact that fuel is leaking out of what looks like a damaged hose mean that air has now entered the fuel system?
2. Am I correct that, assuming the hose is now de-pressurized and I can replace it, after installation I will need to pump the air out of the system manually with the plunger pump near the hose end?
3. Is there anything else I need to do before I start the engine again?

Thanks for considering my questions. I have done all my own basic servicing on the tractor since I bought it. I’m hoping my luck holds out and I am able to get it going again.

 

[piper184]

That is the low pressure line from the lift pump to the filter. It is easy to replace and you should be able to purge any air using the normal primer/purge procedure you would use when replacing the screw on filter. There won't be any pressure in it when the engine is not running.

Also, if you want, you can easily cut off the crimped ferrel at the banjo fitting. I used a cut off wheel in a dremel tool, but careful work with a hacksaw will do the job. Cut around the base and one lengthwise will release the crimp from the hose. Then slice down through the hose lengthwise with a knife to release the hose from the barbed nipple on the banjo fitting. Then the hose should pull off. You can then install new hose of the appropriate size using screw type hose clamps.

Let us know if you have any questions and report back when you get it fixed.
Best of luck!

 

[jonasthaler]

Thank you so much, piper184! I pictured diesel spraying in my face while I scrambled for a bucket or some rubber plugs. And I wondered whether the banjo(s) could be left in place. I will use this method, with my Dremel cutoff tool, if the part I ordered has the wrong size banjos.

 

[jonasthaler]

Update and two more questions: I replaced the upper low-pressure hose, purged with the little hand plunger, tried to start the tractor. The new (silver braided) hose was fine, but fuel mmediately started spurting from the lower hose. Obviously I should have ordered two new hoses, but I only had one. So I created a new one with the old banjo fittings and a length of fuel hose, with double hose clamps. The black fuel hose is for regular gas connections, like carburetors, etc, and it even has "Not for use with fuel injection systems" printed on it. (Question #1) Will this regular gas tubing hold the pressure? The diesel mechanics at the local truck shop said there's nabob reason why it won't work on the low pressure side of the system. I was able to start the tractor this time and it's mostly tight. There is a bit of dripping that looks like it comes from the purge pump. (Question #2) Is it possible that it overflowed a bit when I purged it --it seems to be slowly drying up. Thanks again.

 

[jonasthaler]

OH DUMB ME. I replaced the wrong hose, that is why "the other hose" still leaked. Anyway, they are both new now. DOH!!!

 

[piper184]

Both of those hoses are on the low pressure side. I would be surprised if it exceeds 10 PSI on either one.

The sealing washers on the banjo bolts may be leaking a bit. They may have work hardened. I don't know if they are aluminum or copper. In either case they can be annealed back to a soft state and re-used, or simply replace with new washers.

The black fuel hose you used will be fine with diesel. The warning about injection was for cars where there may be 50 to 100 PSI coming out of the fuel pump going to the injector rail. Not an issue here.

In order to check for leaks, get a can of spray brake cleaner and hose off any areas that appear wet. Wait for it to dry or use some compressed air to speed up the drying. Then start the tractor and test for leaks by touching a clean white paper towel to areas you suspect are leaking. If you are using dyed diesel it will show up easier.

It is quite possible the plunger on the hand pump is seeping a little. They are easy enough to take apart and put in new o-rings.

You did turn the hand pump plunger clockwise to tighten it, right?

Oh, one more thing. When was the last time you checked/changed the oil in the injection pump governor?

 

[jonasthaler]

Thanks so much! Two new concepts. I will check the tightness on the purge plunger and look into the injection pump governor. (During the Age of Dinos I once took a diesel mechanics class, but it was totally theoretical, and I have forgotten almost all of it.) I noticed that the washers on the banjo fittings needed some good solid tightening. I used a bit of diesel on my finger as an assembly lube before tightening down. Some are copper but a few were thicker and of a gray metal, possibly aluminum.

 

[jonasthaler]

Also BTW Thanks for the psi tip. The hose says the pressure limit is 50psi, so I will definitely be fine on the low pressure side of the fuel injection system. This is great to know.

 

[JimRB]

When I am working around fuel system items like that I will get my purple degreaser and clean up as much as possible before taking things apart. Or clean, scrub and rinse with mineral spirits.

 

[stevem5215]

And when was the last time you changed that fuel filter ? It looks old and crusty is why I'm asking. I changed mine every year at the beginning of the season. So much dirt in the tank and clogged screen. I got my hoses when the broke from Affordable tractors. Order on a monday received by Friday. Fixed it every time thanks to him. And those crush washers. Replace them for cheap too. They will leak.