MP5 Issues

[Smokey]

Hey guys,

A friend of mine purchased a MP5A4 a few months ago. He purchased it from Airsoftshop and went with the 400 FPS upgrade (The standard FPS for the group I play with). After a few weeks with the guns the selector switch kept jamming. The gun was taken apart and then put back together, the selector switch was fine. However, after being a fired a few times, it made a horrible shrieking sound and refused to fire. The pinion gear on the EG700 motor stripped.

The same friend put in an order for another EG700, he came to the conclusion that the reason for the first stripping was because he used the wrong screws to place the motor back inside the gun. (Allegedly he used the shorter screws that "incorrectly" mounted the engine in the gun). So he places the engine into the gun, we go outside to test it out. First magazine is great. Now, we switch to full auto, start shooting and suddenly SHRIEEEEEK... motor 2's pinion gear has stripped.

I tell him that perhaps it's the battery he's using, a 2000mah 9.6 volt. He orders yet another motor and also a 8.4 volt battery. He installs both of them into the gun, tests the gun again. SHRIEEEEEK.

I'm completely clueless as to what the problem could be at this point, ANY input whatsoever would be appreciated. Thanks in advance!

Smokey

<edit> Spelling errors </edit>

[Ice]

Well i do own a mp5 and have down a lot of research about them and how to upgrade them. But i am in no postion to be telling you how to fix it. My first guess is did you do any other upgrades beside the spring, gears, mechbox nylon bushing things? If you want someone to fix it right take it to wolverine tactical by grand haven

[Minky]

I would've emailed AirsoftShop first and asked them to try and diagnose, but it's a little late for that now.

Do you know what exact parts were used in the upgrade? It sounds like the motor is out of adjustment, and if he's messed around with the screws and stuff in that area, that's probably it. The center screw in the grip of the gun that comes with Marui's red loktite stuff on it is the motor adjustment screw. I'm not experienced in this area since the Ver. 3 mechbox on my AUG has no motor adjustment screw, but perhaps you can find some more in-depth information about setting the proper motor height at AirsoftPlayers or AirsoftZone.

If it's not the motor being out of whack, it might be the gears in the mechbox. Maybe the wrong type of gears were installed at the time of the upgrade, or perhaps they're incorrectly shimmed, causing them to bind.

I think the best bet would be to email AirsoftShop themselves, since it's their upgrade job in the gun. Good luck!

*edit* Just wanted to check, but I'm betting the fuse was removed during the AirsoftShop upgrade? If the fuse was still in there it might have saved a few motors from being eaten. I never have understood that part of most retailers upgrade plans...the fuse is your 1st line of defense so that major parts in the gearbox don't get destroyed!

[Newman]

Sounds like the gears inside the mechbox are getting stuck. When you say "open up" the gun, does that include the 'box?

Incorrectly shimmed, perhaps, like way way too much shimming...that could jam them...or, one of the gears isn't holding correctly because of a broken bushing. Lots of things. If you open up the mechbox and have no idea what's wrong (that happened with me and the MP5, before I knew what everything did), take a picture and post it here. A couple guys, myself included, might be able to help.

Maybe one of the contacts between the gears is messed up...hrm...

EDIT: Minky and I thought shimming...that's possibly it.

[Smokey]

Hehe, Like I said guys. This is all my friend. He's got some background in mechanical engineering but I'm sure it's not helping him in this situation. And since every time I go over there the gear is already stripped I cant help him.

I'll ask him to take some pics of the internals to show what's going on.

Thanks for all the replies,

Smokey

[WTS-Mike]

2 things to check, either the motor is not engaging fully or yes something internally is bound (many possibilities there)

1. MOtor not engaged fully:

a. is the little metal disc in place that sits precariously on the back of the motor? sometimes this magnetically flips to the side of the motor as the end plate is replaced, allowing the motor to slide away from the gears and therefore strippage begins, no natter how tight you crank in the little allen adjustment on the bottom. It still will only partially engage, and then strip out the pinion gear.

If this is intact, I'd say internal problems abound.
get with the retailer and see if he will cover it somehow, or else we can take a look at it. and give you and estimate.

Mike

[Bigmack]

i'm leaning twards the shim job option. i've seen it happen before on my G3 and MP5. the Mechbox gets screwed too tightly together and crimps a gear so hard that it resists the motor completely.

[Smokey]

Well I copied all your suggestions into e-mails and sent them off to my friend. He replied today saying thanks that he got it to work. I'm not sure which solution it was, but he replied to the one with Mike's advice so I'm thinking that may have been it.

Thanks for all the help gents, you can lock off the topic if you wish.


Smokey

[WTS-Mike]

Well No matter whose advice, as long as another airsoft gun is restored to active duty!!

*In shrieking pain filled voice, but still trying to sound cool*

"Yeow!!, Hit, Hit, HIt!!!"

[Juggy]

Guys,

Mucho gracias. When I took the MP5 apart and put it back together, I must have not noticed that the motos adjustment screw in the center of the grim came loose.

After adjusting that screw and using some lock tight thread gel, things returned to normal. This is my brother's mp5, and he was loosing faith in me and the sport, I'm very thankful for all your suggestions / tips and help. You guys rock.

-Juggy
dtct.recongamer.com

[Got myself an account D]

w)()(t

[Juggy]

Got said:

w)()(t

Never mind... I'm such a noobie.