My M4 AEG wont fire

Discussion in 'Gun Building, Modifications & Repairs' started by ArielNechemia, Oct 22, 2012.

  1. ArielNechemia

    ArielNechemia New Member

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    Hi all, i have a M4 AEG and it wont fire anymore, it has this sound of gears but like gears going in two different direction, or like gears running against a sheet of metal. Is there any thing i can do?:confused:
     
  2. Rainbow

    Rainbow New Member

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    Who manufactures your m4? And have you opened it up yet?
     

  3. dylan484

    dylan484 New Member

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    Tifton
    Take it apart and look in the gearbox
     
  4. TYSONtheSNIPER

    TYSONtheSNIPER New Member

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    Edmonton
    Are your motor connections on right? (red to red side black to black).
     
  5. ArielNechemia

    ArielNechemia New Member

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    My gun is a G&G one, i think that the gearbox is all put together correctly, i think i might not have put in the motor correctly, it doesnt have any color markings on it.
     
  6. Star_folder

    Star_folder Active Member

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    Lexington
    So you took it apart, put it back together, and now it won't fire?

    If all the gears are in one piece, and nothing is terribly damaged, your motor height could be way low, just barely touching the bevel gear. Did you adjust the screw on the bottom of the pistol grip when you took the gun apart?
     
  7. ArielNechemia

    ArielNechemia New Member

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    Im pretty sure the gearbox is placed properly, i checked twice. I didnt adjust the screw at the bottom of my grip, is the motor supposed to push out when trying to fit it into the grip?
     
  8. gReaper

    gReaper New Member

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    Check the gearbox one more time see if the gears are out of time and if thats fine then you just need to tighten the motor adjustment screw in your hand guard
     
  9. Star_folder

    Star_folder Active Member

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    Lexington
    There's no such thing as gear timing. If he hasn't messed with the motor height screw, then he shouldn't mess with the motor height screw.

    It would seem, that you've not put it back together correctly. At this point, it'd rather difficult to tell you exactly what's wrong with your gearbox. It's possible you can take it a part, and put it back together and it will work. But taking it apart is a good idea regardless. If stuff is grinding, that means you're damaging parts in the gearbox, you should check to make sure they aren't damaged so much that they won't work any more.
     
  10. gReaper

    gReaper New Member

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    Someone has never been in a gear box before if you dont think there no gears in the gear box that need to be timed
     
  11. Thestig

    Thestig Some say... Supporting Member

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    Colorado Springs and Southern California
    Star_Folder is one of the best techs in the world right now. He knows what he is talking about.

    The only thing about timing I can think of is putting the selector gear to where it is in no contact with the piston while putting the gearbox back together. But even if you don't do that, it just rotates once, and is fine.
     
  12. Star_folder

    Star_folder Active Member

    1,056
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    Lexington
    Then let's examine this. Gear timing would suggest that if the gears aren't placed together properly, then the whole gun will cease to function, for any number of reasons. However, examine your gears, look at how the whole system works.

    The bevel gear, only turns in one direction, and is symmetrical. Doesn't matter how you put it in, because it will always turn the same way, regardless of how it's installed.

    Spur gear, same as the bevel. Very simple step gear, only turns one way, can only be installed 1 way, and will turn the exact same way regardless of how it's installed in the gun. Go figure, its perfectly symmetrical.

    Sector gear, ohp, there's a difference, it's not symmetrical. It's got 15 teeth, a cut off lever cam, and a tappet plate cam. If you'll notice, regardless of how you install the gears, it will always spin in the exact same way. The cut off cam will always engage the cut off lever at the same time, and the tappet plate will always be engaged at the same time. Regardless of how the gear is installed into the system. The gears will always rotate around, pulling the piston in sync with how it cuts off the current with the cut off lever and how it pulls the tappet plate back and releases it. The only possible thing you could be thinking of, is turning the sector gear in such a way, as to make it easier to close the gearbox. Easiest thing to do is turn it so that the tappet plate cam is just before it engages the tappet plate. The Piston teeth aren't engaged, it's just after the cut off lever has been engaged, everything is at rest, meaning the rest of the gun is easier to put together.

    I mean, if you really wanted to, you could try installing the piston onto the sector gear with the whole system half way pulled back, but besides needing special equipment and making it incredibly difficult for you, there is no such thing as gear timing within an AEG.
     
  13. ArielNechemia

    ArielNechemia New Member

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    Thanks, I will try that out.
     
  14. Bootskoot589

    Bootskoot589 New Member

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    I need help as well. I just recently got a new G&G Combat Machine variant and installed a new spring. To put it simply, I got the shell on, put it all together, put the motor in, test fired... click. What? Click click.

    The motor is trying to move, I can hear it, but it's really quiet. No gear movement, just the motor trying to spin. Very little noise.

    Did I possibly wire it backwards how I was supposed to? I know exactly how to put this rifle back together but because I was up at 1:30 in the morning simply trying to get the shell back onto the gearbox and losing one bushing (little shiny disc that goes on the gear lol let's say that cuz I can't hardly ever use the correct term for things) I may have gotten careless and anxious to reassemble the rifle. It wouldn't fire or move whatsoever other than the motor trying to rotate.

    Should I open the gearbox again or is my motor the issue either with the wiring or even something not doing it's job in the gearbox?
     
    Last edited: May 9, 2014
  15. SweetJerk

    SweetJerk New Member

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    Merritt Island
    Maybe your battery is dead? I know that's probably not helpful but I have had an instance or two where I just forget to charge
     
  16. Carpathia

    Carpathia Active Member

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    Springfield
    It sounds like you've wired your motor backwards. If you put the wrong wires on the wrong post, the motor will try to spin backwards, and the ARL prevents the gears from turning backwards. Make sure that the red wire is hooked up to the positive lead on the motor.
     
  17. Bootskoot589

    Bootskoot589 New Member

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    Yeah I knew that, I was just making sure that sounded like the problem to someone more qualified of knowing xD
     
  18. Bootskoot589

    Bootskoot589 New Member

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    Lol SweetJerk I didn't forget to charge my battery ;)
     
  19. killerbee

    killerbee New Member

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    Also, check to make sure your motor is moving freely up and down inside of the grip. If it wasn't installed correctly and the wires are causing it to bind in the grip then it may be pushed too high. The motor should spring back whenever you push down on it with your finger as you are installing it. If it doesn't move as described then the adjustment screw cannot do it's job.
     
  20. Bootskoot589

    Bootskoot589 New Member

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    Alright thanks looking at that now. The gears and bushings seem to be in place from looking at the gearbox without taking it apart but I also did tighten the screws pretty good on it before, I'll try to make sure it's all good