Kubota Electric lift pump failure? Ever happen? No start issue. Gelling?

[kuboman]

Kubota along with most manufactures use a lift pump to make bleeding the fuel system after a filter change much easier. A simple very reliable design.

[Chilly807]

Diesel shouldn't gel at -7C in my experience.. any chance there was a bit of water in the fuel?

Sean

[Scooby074]

Diesel shouldn't gel at -7C in my experience.. any chance there was a bit of water in the fuel?

Sean

Shouldnt have been. Fuel was bought at a station that moves a fair bit of diesel, but you never know what crap was in the tank *cough*Irving*cough*

[Scooby074]

Lift pump from **** strikes again!!!

Tractor started and ran fine down to get the garbage but stalled out in the yard. Fuel pump rattle is intermittent. When its rattling , tractor will start but die quickly once its stops.

Were currently in a cold snap, -15C here now. It was working fine up to today since the last time, in temps from -5C to -12C. Fuel in the tractor's tank is treated with both 911 and PS white. I dont know if there is gelled fuel causing the pump issue or if the pump is going bad????? Messicks lists it for about $100, but up here I wouldnt be surprised if its 2x that. I dont want to go throwing $200 pumps at it if Im having a water issue.

I have a brand new Racor 120A filter that is going on the tractor as soon as its in the barn again. Matter of fact I called Racor's tech line (excellent by the way) to see if I could mount it downstream of the lift pump to make hookup easier. They said that while it would sort of work with the 2micron filter, the best and recommended place is before the lift pump so that any water isnt emulsified by the pump action. I dont know if im having a water freezing issue or gel issue today, but I wish I had put that filter on last time the tractor was in the barn.

Im also going to try and find some Kolor Kut and dip my tank to see what, if any water may be in it. Kolor Kut is likely going to be hard to find in these parts. We always had it at work but I have no idea where it came from.. The tube of the stuff is likely older than me...

[Scooby074]

Some video of the intermittent pump:

[Scooby074]

Second video. Even though the loud clicking stops and starts, the pump continues to emit a low purr. I think the pump is fine.:

[Scooby074]

Fuel flow looks much lower than I expected. Im strongly starting to think that the filter upstream of the pump is partially plugged either with ice, dirt or wax, and the lift pump is OK. I intend on bypassing the filter tomorrow to try and limp the tractor home.

[David_Kb7uns]

I am thinkinmg that once it builds up pressure the slug in the fuel pump is held to one end of the bore by the fuel pressure and that is why it stops making the noise. I think if you started tractor up it would probably run all the time.

David Kb7uns.

[Scooby074]

I am thinkinmg that once it builds up pressure the slug in the fuel pump is held to one end of the bore by the fuel pressure and that is why it stops making the noise. I think if you started tractor up it would probably run all the time.

David Kb7uns.

I dont believe that there is any type of pressure switch on this pump (certainly could be wrong though). For as long as Ive owned it, the pump has made the loud rattle whenever the key is on, engine on or not.

Where I am now, Im thinking that when the pump runs out of fuel due to a blocked filter, it gets quiet. Then whenever there is fuel present to be pumped it gets loud again.

Best way to see would be to pull the fuel supply line off the injector pump and see what is coming out. If it is coming in spurts the Im pretty sure there is a blockage somewhere.

[David_Kb7uns]

No pressure switch on pump metal slug with check valve and check valve on input. Slug is pushed by spring and then the magnetic field kicks in and propels against spring then it is pushed by spring again. Grit, fuel gelling or whatever will keep the slug from going back and forth the magnetic field generated by the coil is not very strong. The fuel stream will not be constant but will have pulses in it.

David Kb7uns