Hey everyone, thanks for the add. I have been reading through some older posts, and can't find the answer. I have a 753 C-Series, 512726223 with about 800 hours on it. The issue is, is that after about 20min loses power and shuts off. I have replaced fuel lift tube and filter, lift pump, hand primer, fuel lines are all good, multiple fuel filters. I have tried with my fuel cap cracked, I have ran out of different fuel source and same thing. Primer has never been sucked flat. If I walk behind it while my son drives, i can keep it running with the primer bulb. It seems like when it gets warm, that is when the problem happenes. If I let it sit for 1-2 hours, no difference. But if it cools all the way down like I've waited 6 hours, then it is fine for another 15-20 minutes. I did just get a new fuel cap since they are cheap, just haven't had a chance to try it yet. Great stuff on this site, and thanks for any of your guys help/knowledge...
753 shutting down (like running out of fuel)
- Thread starter Kuchball
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flyerdan
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The symptoms you describe sounds like it's getting an air leak somewhere between the primer bulb and the lift pump, since you can keep it lit with the bulb when it starts to die.
I know that you've replaced almost everything that could cause this; perhaps add a small electric impulse pump between the tank and primer and see if that sorts it.
If there is an air leak when it warms up and expands, there should also be a corresponding wet spot when you pressurize it and let it sit for a while.
I will look at that tonight, thanks for some imput!!
Nothing wet under fuel lines, ran with new fuel cap as well. Still wanting to stall.. Anybody anybody?????
You have pretty well exhausted everything i can think of.
The only thing that hasn't been mentioned is the bleed screw, can you confirm it is turned off tightly? if it's left open after priming, it will run at first, but then stop as there will not be enough pressure to keep the injector pump happy.
As squeezing the hand primer being it back to life, it has to be a fuel pressure issue, yet the lift pump was replaced. If the bleed screw was open, this pressure may not be high enough.
rjitreeman0909
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Is there a manual shut off valve? Kink or pinched supply line? Is there a screen or filter on the inlet of the main pump? Similar to GM carburetors.
There is no shut off that I am aware of, as it was running fine until a couple weeks ago when this started. The main pump (lift pump) no screens, pump out just fine when I turn key. I was reading some other posts, where they were talking about the relay. the starting solenoid clicks on strong, but is there the hold part of it that could fail after it gets hot?? The arm/linkage is always to the right when it stops. I didn't know if that was what the hold is, or if it holds a different valve open. So puzzled but trying to stay away from the dealer... Thanks again everyone
flyerdan
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If it has an ignition switch controlled fuel shutoff (as opposed to the cable pull to shut down), that isn't your issue as no amount of primer bulb pumping would keep it lit; it just shuts down instantly.
Is the exiting lift pump electric, or engine driven? I could see a diaphragm pump getting a small tear that would prevent it from developing full pressure, but that would be spilling diesel into the oil, and replacing one with one that has the exact problem is unlikely.
Since about the only thing that hasn't been replaced or addressed is the injector pump, it's high on the suspect list. Perhaps there is some internal failure that only shows up under heat expansion. That would require special equipment to troubleshoot, and might not be repairable if it's a fracture or such.
I'd try a parts store electric pump to substitute for you walking behind and priming as that's probably the easiest and least expensive stop-gap measure.
Thanks Flyerdan, I will try that. Any 12v fuel pump do? The most common ones I found are low psi 2-4 and others are 5-9 psi.
flyerdan
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Since it's a diesel you don't need to worry about flooding the carb, so I'd opt for the higher pressure one. The squeeze bulb probably puts out 35-40 psi easily, so over pressure isn't an issue.
When it starts to die and you use the bulb to keep it going, how much pumping does it take? If it just takes a couple squeezes to keep it lit, the aux pump should do the trick; if you frantically have to pump until the bulb is solid that indicates bigger problems that the aux pump probably won't solve.
Fuel shutoff has 2 modes. Lift and hold. Lift pulls the solenoid in hold holds it but if that shut it off pumping the primer bulb wouldn't help.
I pump like half a pump to keep it going. The bulb is still hard so hopefully that works, I have one on order. farmshop, that is what I have heard about the two modes, but didn't know if that would totally shut off fuel. So puzzled, trying to get this landsape project done, and it sure sucks using the bobcat 20 minutes in morning, and 20 minutes in evening. AHhhhhhh
Well I finally got that fuel pump installed, still does same thing, unhooked fuel line where it goes into injection pump and fuel flows great all the way up there. Is there a possibility that my injectors could get clogged after they get warm and gum up?
Doubtful. Have you tried running it from a separate can? I wonder if it sucks something up onto the pick up screen in the tank
Yes I have tried another can, when it stalled last time I dis-connected the fuel line up by the injector pump (by the bypass shut off) and I had fuel pumping out good with my 12v fuel pump running. That is why I was wondering if it is up line from there, next place fuel goes is into injectors...
Any other ideas out there...anything electric or wiring related I could check......
bobbie-g
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Kuchball, I'm outta good ideas like the other folks that commented. So here's a goofy one: you could use a heat gun or hair dryer to heat up the injector pump and see if that causes a failure before 20 min. Of course, you now have an ignition source close to fuel with the dangers that entails. But the first thing to do is get one of the el cheapo Harbor Fright IR temperature sensors and see how hot the injector pump and lift pump are, right when it stops after your 20 minutes. Then you'll know how hot to heat them up. I would start the engine cold and let it run for 10 minutes, then if it's running fine, shut it off, get the fire extinguishers read, and heat those two components up to a bit above the temp you measured when the engine quit from heat stroke. Then try to start and see what happens. As I said, not the best idea, but maybe worth a shot, especially in the absence of other ideas.
---Bobbie-GThanks for the idea, I will concentrate more on the temp stuff next time I have some time. I will make sure to let ya'll know what is causing this when I find out...Kuchball, I'm outta good ideas like the other folks that commented. So here's a goofy one: you could use a heat gun or hair dryer to heat up the injector pump and see if that causes a failure before 20 min. Of course, you now have an ignition source close to fuel with the dangers that entails. But the first thing to do is get one of the el cheapo Harbor Fright IR temperature sensors and see how hot the injector pump and lift pump are, right when it stops after your 20 minutes. Then you'll know how hot to heat them up. I would start the engine cold and let it run for 10 minutes, then if it's running fine, shut it off, get the fire extinguishers read, and heat those two components up to a bit above the temp you measured when the engine quit from heat stroke. Then try to start and see what happens. As I said, not the best idea, but maybe worth a shot, especially in the absence of other ideas.
