The truck won't re-start when hot and I'm pretty sure the problem is in the circuit that provides voltage to the fuel shutdown solenoid (mounts on injector pump). I've replaced the solenoid and installed new filter before that. It will run all day but after it warms up you shut it down and try to re-start it will turn over but won't fire until it cools down, anywhere from 2 to 3 hours, I crack the line at injector and there's no fuel pressure. I don't have a wiring diagram so thought I would post here to see if anyone has had similar problems. Bobcat Model-S160 Serial-529912344 Any help appreciated, Thanks, Dino54
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OldMachinist
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Have you checked to see if you're getting power at the solenoid. Wire number 8100 is the pull voltage and wire 8800 is the hold voltage. Wire numbers are printed on the wires. While cranking you should have voltage for the pull coil and it comes from the fuel pull relay. If no voltage during cranking then the relay is likely bad. Try swapping the fuel pull relay with the lights relay. If that doesn't help look for corrosion in the fuse/relay block(both sides).
Thanks for the replies, I failed to mention that I already traded around the relays, I'll check relay panel for corrosion though. I also checked voltages at solenoid, if I remember correctly (not near truck ATM) the outside smaller yellow wire had battery voltage and larger yellow wire had around 7V, both during cranking. I'll re-check in the morning and post results. I assume the pull voltage is at start and hold V is constant? Thanks, Dino54
Next time it happens check the fuel tank to make sure the cap is venting as it should.
Always replace the relay when replacing the solenoid. I have been burned by that. Also make sure you are switching the right relay, the diagram on some can be a little difficult to orientate. Also check the wiring coming from the solenoid. I have seen quite a few rub and cause intermittent problems. Any problems with the solenoid and it should set a code. When it won't restart, pull the solenoid out. If that is the problem, the engine will start. You can snub the engine by running against the brake. I'd check to make sure the primer bulb isn't collapsing. This is a sign the engine is trying, but can't get fuel. I haven't seen it in a while, but had a rash of bad fuel caps not allowing the tank to vent.
Thanks Jerry & Bobcatdan, I'll check all that and report back.
Ok, I started the truck this morning, let it run for 1/2 hour, shut it down and it failed to restart, I checked fuel prime bulb- not collapsed, removed fuel cap and still no restart. I then removed fuel solenoid and it still wouldn't start so that eliminates that. The only other thing I can think of is a weak fuel pump but that doesn't make too much sense to me as the truck will run and operate all day with plenty of power. I guess it's possible that when hot it's too weak to pull fuel to the injector pump? It's not a common symptom for a bad fuel pump but I'm running out of ideas. Advice anyone?
When it doesn't restart, try running it off a can of fuel. That will tell you if the problem is with the pickup and fuel line or not. The transfer pump next to never fails on a Kubota and if it does, it just does. I'm think the fuel rack is sticking. That is what the solenoid pushes against to control fuel delivery. With the solenoid remove, does it move freely when the engine doesn't start? In the off position, the solenoid pushes it down. With the solenoid out, spring tension pushes it up to the run position. You can stick your finger and push on it, it should move freely.
I'll check the fuel rack for free movement, thanks.
A final follow up to this thread. Bobcatdan was correct, the fuel rack was sticking, preventing proper fuel flow. Thanks to everyone for their input.
What did you do to free up the rack?
