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Caterpillar 3412 stuck injection pump rack

Discussion in 'Other Earthmoving Equipment' started by excavator, Dec 4, 2019.

  1. excavator

    excavator Senior Member

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    Had a customer call this morning with a 3412 mechanical engine in a grinder, it's been sitting for years and when it was recently started it runs at approx. 1200 rpm and is stuck there, won't idle up or shut down. They pulled the solenoid and said the rack in the pump is stuck, any idea's on getting it freed up? The machine is about 2500 miles away and he has someone over there working on getting it up and running for transport so I have very little info. I know it's pretty vague but any thoughts?
     
  2. Nige

    Nige Senior Member

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    John C. likes this.
  3. kshansen

    kshansen Senior Member

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    Any chance of a S/N or any numbers off the pump?
    As always the more information put in the more information that comes out!
     
    excavator likes this.
  4. excavator

    excavator Senior Member

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    I'll see if we can get anything, like I said 2500 miles and I have no idea who's working on it. :)
     
  5. excavator

    excavator Senior Member

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    I just talked to the owner and he has an arrangement number- 38S18049
     
  6. Nige

    Nige Senior Member

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    That is actually the Serial Number. Arrangement is 6N-1155. Here's what the injector pump looks like.
    I'm not even going to express an opinion whether or not the rack could be freed off out in the bush.

    upload_2019-12-5_6-18-25.png
     
  7. kshansen

    kshansen Senior Member

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    Well in my opinion if your name here is pumpguysc I'd say maybe a 50% chance of freeing the rack up in the bush. But for anyone less skilled I'd have to drop that chance of success to about 2%.

    But if you do decide to give it a go be sure to set up a cell phone a safe distance away and turn it on to record the initial start up! Be aware that most pieces flying out from a run-away engine will go out the sides so have cell phone positioned so it doesn't get damaged!
     
    mg2361 likes this.
  8. Manu

    Manu Active Member

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    The governor is driven from the pump from a vertical shaft .It sounds like the drive to the flyweight assembly has failed or flyweights have broke through the thrust washer. If a new shaft or flyweight assembly is unavailable the complete governor could be changed. In any case a governor " runaway" is a very dangerous event so it should not be attempted to be repaired by someone not qualified or experienced with such matters. I speak from such an experience with a D9 D353 engine.