Need help with Kubota KX040 FUEL PROBLEM

   / Need help with Kubota KX040 FUEL PROBLEM #21  
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


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   / Need help with Kubota KX040 FUEL PROBLEM
  • Thread Starter
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.
checking lift pump.jpg

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.

bypass water separator_9427.jpg

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.
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