Need help with Kubota KX040 FUEL PROBLEM

[R44]

This what I found on mind the return fuel line coming from the cooler was off and the clamp damaged
it would hiccup every so often (loose hose) then finally came off and would not run
could not see the hose with the counter.weight on
22mm bolts for the CW

 

[Sodo]

I found "looseness" at the lift pump connection too, same as your pic of the spring clamp (moved). So someone was working on your lift pump before you. All I could do in the limited access, was move the clamp closer to the bead.

Yeah that counterweight makes it very difficult to access the lift pump.
Here's how I accessed the lift pump. If you do what I did (in my pic) ---- you improve pump access "just a little", like 10%. If I saw your pic..... just seeing your pic .....I would have taken the counterweight off. I didn't have overhead lift, I would have to rig something, but it's difficult to self-lift the counterweight.

Try bypassing the water separator. I wiggled the water-separator fittings andit was feasible to let some air in there. They are press-fit. I took them out and re-sealed them.

As said above, I was able to "improve" the operation but in the limited time I had to work on it, I never solved the problem.

But to have that situation (injection pump sucking air in) suggests the lift pump was unable to supply the injection pump's flow requirements at full-power. So the air is an "indicator" that there's a vacuum in the supply - there should be NO VACUUM. The real problem is the injection pump is not receiving "positive pressure" from the lift pump. It could be a faulty lift pump or perhaps intermittent electrical supply.

 

[ESAM]

Just in case anyone else has a similar issue and is struggling to find a cause for one of these machines that will turn over but not start. Mine was in this state for awhile and I started going through some of the fuel feed possibilities. I was just about to pressure test the fuel rails and decided to wait for a while and get the batttery charged up all the way since it has been sitting for a couple of months in the cold with little use.

After charging the battery for awhile the machine fired right up and continued to fire up after turning it off a couple of times. I do remember this happened the year before also but I must have forgot.

Just wanted to toss this info in here as a very easy possible solution to such a problem as a Kubota KX 040 cranking over but not starting.

 

[thclimer]

Just in case anyone else has a similar issue and is struggling to find a cause for one of these machines that will turn over but not start. Mine was in this state for awhile and I started going through some of the fuel feed possibilities. I was just about to pressure test the fuel rails and decided to wait for a while and get the batttery charged up all the way since it has been sitting for a couple of months in the cold with little use.

After charging the battery for awhile the machine fired right up and continued to fire up after turning it off a couple of times. I do remember this happened the year before also but I must have forgot.

Just wanted to toss this info in here as a very easy possible solution to such a problem as a Kubota KX 040 cranking over but not starting.

Welcome to TBN!

Glad you found your issue, sometimes it is just the simple things.

 

[Sodo]

I had similar trouble, it just "chuffed" white vapor out the exhaust.
I'm pretty sure the cause was an old battery, and the cold weather.
Not enough CCA (Cold Cranking Amps).

I'm thinking it was sucking the glow plugs "dim".
And not turning fast enough.
I was able to start it running a 15 Amp heatgun blowing hot air into the engine air intake.
(using a portable generator)
Another guy suggested maybe I still had "summer diesel" in it.
Yes I did have Summer diesel in it.
Trouble......

But I put in a new battery and all those troubles disappeared.

This is UN-related to the topic ( KX040-4 that would stumble at "full power". )