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2012 Big Blue 300 Pro with a Kubota engine problems

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  • Shanebob
    started a topic 2012 Big Blue 300 Pro with a Kubota engine problems

    2012 Big Blue 300 Pro with a Kubota engine problems

    Bought the machine used several months ago, really like the way it welds now but I am having issues with it shutting down while welding. The hour meter - fuel gauge reads "Lo Oil Pressure" this is not a constant issue only sporadic for some reason, checked to oil pressure sending unit it seems to be functioning just fine. The machine can be shut off and later on in 10 minuets it will run just fine? it was well maintained by the prior owner, has 4775 hours on it, The work I do with it is pipe welding, So far it has held its own against all the Lincolns here at work but the first little hick up I get pounded on, I know its got to be something simple but it is a complicated machine vs what I am used to using ( Classic II 250 Lincoln). The only thing I have done to it is service it and lower the Hertz to what Cruiser suggested, which made a huge improvement to how it welded, that adjustment should not have affected the oil pressure safety system on the machine. any advise appreciated.

  • duaneb55
    replied
    The OP switch is NO (Normally Open) with no oil pressure. If functioning properly the switch will close to ground with more than 4psi which is what the hour meter/fuel gauge module is looking for. Pulling the wire off would be simulating a low oil pressure condition and shut the unit down as it should.

    To check for a faulty OP switch, one needs to ground its wire manually or with a jumper from the sender terminal to ground with the wire still connected to the switch. If the unit continues to run with the OP switch wire grounded then the switch is bad.

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  • Shanebob
    replied
    Yes the machine is full of oil, checked that first thing and it will shut it’s self off if the wire is pulled from the pressure switch, have not used it much since last week, have some 30” and 12” tie ins all day tomorrow will see what it does, I ordered the oil pressure switch last Sunday but have not received it yet to install it. Thanks for the input will see what happens tomorrow.

    Leave a comment:


  • Popscott
    replied
    Yes... I have seen engines with border line oil levels that will not run on an incline but will when unit is level..

    Again.... pull the wire off of the pressure switch and see if the engine shuts off 30 seconds after it is started.. It is not a sure fire conclusion but may tells us whether the circuit is working...

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  • MasterKwan
    replied
    Originally posted by Popscott View Post
    Or by design... the oil pressure is actually dropping below 4 psi and the machine is shutting off to protect itself..
    This is a good point. It's a good idea to check the oil pressure itself.

    https://www.amazon.com/8MILELAKE-Eng.../dp/B01N98909D

    Disposable chinese pressure tester.

    Leave a comment:


  • duaneb55
    replied
    Guess we all just presumed the OP checked the oil level in light of the LO OIL fault indication but wouldn't that be a hoot. Have seen that with a number of portable generators equipped with low oil level switches.

    Leave a comment:


  • Popscott
    replied
    Or by design... the oil pressure is actually dropping below 4 psi and the machine is shutting off to protect itself.. Oil level OK?
    If you remove the wire from the pressure switch... start the engine... does the engine stop 30 seconds later?

    Leave a comment:


  • Shanebob
    replied
    Thank you for your help!

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  • duaneb55
    replied
    Originally posted by Shanebob View Post
    Nice! this is getting really technical! I understand what you are saying about the control relay I believe. I don't have it off yet but in looking at the Section 9 Electrical Diagram it looks like it comes off the number 7 connection on the fuel hour meter, would it be wise just to replace it along with the fuel hour meter at the same time to eliminate any weak links? thank you very much for the advise sir.
    I know you depend on this machine to make you money every day but I don't like to "poke-n-hope" by just changing a number of parts at once UNLESS I know for a fact they are all bad or have been compromised by another component failure. Hence the troubleshooting suggestions. Systematic process of elimination that might save you some $$$ and know for sure what the cause is as well.

    Correct on pin #7 which should be wire #54. Pin #7/wire #54 is the ground path for CR1 and with a fault indication there should be 12VDC(+) on wire #54 with the ignition switch in the RUN or RUN/IDLE positions. This voltage would simply be 12VDC(+) feeding thru the coil winding of CR1 which would not be energized due to the lack of a ground thru the hour meter/fuel gauge unit on pin #7 as the result of a fault trigger. Under normal conditions with no fault trigger and unit running, there would be no voltage reading between pin #7/wire #54 and ground.

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  • 1997CST
    replied
    If you are standing in front of the machine CR1 is located on the right side, inside the white control box when you take off the side panel.

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  • Shanebob
    replied
    Nice! this is getting really technical! I understand what you are saying about the control relay I believe. Can you tell me where it is located with the hood taken off please? I don't have it off yet but in looking at the Section 9 Electrical Diagram it looks like it comes off the number 7 connection on the fuel hour meter, would it be wise just to replace it along with the fuel hour meter at the same time to eliminate any weak links? thank you very much for the advise sir.

    Leave a comment:


  • duaneb55
    replied
    Another thought.

    Not sure if the meter/gauge would indicate the LO OIL fault if CR1 dropped out shutting the unit down and thus no oil pressure. As long as the meter/gauge remained powered by the ignition switch I think an intermittent failing CR1 (or one of its connections) might be a possible cause to consider.

    Leave a comment:


  • duaneb55
    replied
    The OP switch grounds to its body which means it's a 1-wire device. It's a 4psi NO switch and with no oil pressure the switch opens and the ground thru the body from the engine to the meter/gauge goes away, the ground to control relay CR1 goes away and the engine shuts down. So, simply connecting a jumper wire to the switch terminal from ground can tell you if the switch has an intermittent open fault from ground if the unit no longer shuts down with the jumper wire connected.

    If it continues to shut down with the "LO OIL" indication then the hour meter/fuel gauge unit is likely defective as 1997CST stated.

    Meter/Gauge:
    http://miller4less.com/advanced_sear...=18&search.y=7

    OP switch:
    http://miller4less.com/advanced_sear...16&search.y=10

    Leave a comment:


  • Shanebob
    replied
    Ok, thanks for the advise.

    Leave a comment:


  • 1997CST
    replied
    It's a great machine and for the price you paid it's a steal. Yea the Hour meter has so many functions now that you just have to replace it. Worth it as you can forget about the machine and concentrate on welding.

    Leave a comment:

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