B2920 turns over but not getting fuel

[dgarvin57]

I'm beginning to restore a beat up B2920 and bring it back to life. I've already found a few wiring shorts or opens and now it will turn over but not start. But, if I run 12 volts directly to the stop solenoid bypassing the stop relay and the OPC (I know the stop relay is probably bad or there's at least one more wiring short) it just clickity clicks continuously (I assume this is the stop solenoid but maybe the fuel pump?). If I then turn the key to start it while the clicking is going on, it starts and runs until I cut power to the stop solenoid.

So, looking for some guidance from those with more experience. I can read schematics and trace current but not all that familiar with diesel engines. I've ordered parts (OPC, stop relay), and will probably include a stop solenoid, since in my testing, all of these have shown some problems. But, it may just all be more wiring issues. Thought about just replacing the wiring harness, but that's a pricey part and a ton of work. Else I'll just track down each symptom and replace wires between the parts that aren't working.

If you feed 12 volts to the stop solenoid and it continuously clicks, is that normal or is that in indication of a problem. I know there are two coils and the 12 volts leading from the stop relay comes in on one wire and then splits onto the two terminals of the stop solenoid. I'm guessing this is to feed two coils. The larger coil pushes the shaft to turn on fuel and the smaller coil keeps it there, I think.

Thanks for any ideas.

 

[lugbolt]

the stop solenoid has two coils

one makes the plunger move, high current the other HOLDS the plunger, low current. This reduces the electrical load on the generator and battery, etc and keeps the stop solenoid from overheat

if the hold coil is bad, they will sometimes do that, but so will a bad ground, so you will want to check the ground, properly, under a load and go from there

 

[dgarvin57]

if the hold coil is bad, they will sometimes do that, but so will a bad ground, so you will want to check the ground, properly, under a load and go from there

I did have a bad ground on the tractor. I've replaced the bolt (had to re-tap the nut threads because the bolt wouldn't tighten. I'll be replacing the ground terminal cable and wire brushing the plate under the bolt. I'll see if that clears it up. Thanks.

 

[Mark_BX25D]

There's more than one ground to worry about. Battery to frame is the main one, but then each circuit needs to connect to the frame. Make 'em shiny bare metal, slap on some dielectric grease to keep them that way, and check resistance on the wires.

EDIT TO ADD: Low voltage can cause a solenoid (like your fuel cutoff valve) to chatter like that. The problem can be on the ground or the supply side.

 

[RCW]

Some Kubota tractors do have an electric lift pump that would make that clicking sound.

However, it looks like your B2920 is a mechanical pump, like an older car/truck.

If you don't already have them - Illustrated parts diagrams:

Kubota Tractor Corporation - Illustrated Parts List

- K-PAD - Parts Lists - Illustrated Parts Lists - diagrams

apps.kubotausa.com

A workshop manual would be handy. I checked these two places, but didn't see one with a quick check. Attaching in case I overlooked it:

www.kubotabooks.com

Over 600 free Kubota manuals. A library of free manuals and parts diagrams compiled by Kubota tractor owners. All free to download instantly. No tricks, no subscriptions, no sign ups, no weird apps or software to install.

www.kubotabooks.com

Kubota Tractor User Manuals Download | ManualsLib

www.manualslib.com

 

[dgarvin57]

There's more than one ground to worry about. Battery to frame is the main one, but then each circuit needs to connect to the frame. Make 'em shiny bare metal, slap on some dielectric grease to keep them that way, and check resistance on the wires.

EDIT TO ADD: Low voltage can cause a solenoid (like your fuel cutoff valve) to chatter like that. The problem can be on the ground or the supply side.

Good suggestions. Thanks.

 

[dgarvin57]

The stop solenoid was bad. It should not click continuously when the key is turned on. It should click once. Probably the secondary winding was bad on the solenoid, so the high current circuit pulled the plunger back but the secondary winding didn't keep it retracted, so the primary circuit kept pulling it back: Clickity-click constantly. Replaced and the it started.

 

[BAP]

Good to hear that you found the problem