gearbox
 

sup guys
im a noob and i got in to a hell of a task. i opened my gearbox to change the spring. im a mecanic so i told my self o could do it eaven if alot people told me not to touch it. anyways. i took it apart and put it back together. but now it shoot out the bb 1 time out of 3 and it shoot veeery slow. anyone can tell me what could be the problem?

first problem is u posted this twice lol.
after that is that u shoulda litened to the folks who told u not to open the gear box.
okay now ill stop pokin fun at you, it could be alot of things but id say the loading nozle and tapet plate are likely the issue if its not always feeding and has low fps.
tho it could be any number of things.

what kind of gearbox is it?
mechbox.com has videos to show you what to do to assemble it properly.
the site is down but there youtube is up still.

Where are you located? It may be in your best interest to find someone that knows what they're doing and have them do it for you.

What gun is it?
When you say it shoots very slowly, do you mean rate of fire or velocity?

Find someone to help you, a local airsoft shop is a good place to start. If there are any games or airsoft clubs around, then ask around there. Also, get age verified (if your of age), you will have access to the best airsoft gun doctors in Canada.

You tube, I've chnged my spring 3 times already with no issues. If you are looking for people to help here, pictures and model of gearbox would help.

You probably moved some shims around, shoot until you see your nozzle is all the way forward, then push it in with your finger and see if it moves back and forth freely. If not, you put something together wrong.
It could be as simple as a mechbox misalignment where its just not seated properly in your receiver

So what I ment by slow is velocity.
It's a rdw bravo. Same body and great box ad m4.
So yesterday I notice that the nozzle wouldn't go back.
It was jamed. So I opened the gearbox again and when I put it back together I pushed the nozzle and it was ok. I shot a couple of times and it got stuck again. Maybe Im not puting the sector gear in the good position. When I opened the gear box again I notice that the sector gear turned but only half way. I bought this gun used and there is shims and a plastic thing on sector gear. Does it mean that it was modified? I really whant to do this my self. Don't whant to give up.

the part of the sector gear that has no teeth should be "up" (so no teeth have engaged the piston). Also on the face of the gear is a peg that pulls the tappet plate back once a revolution.(once for every smooth part on the sector gear). A triangle part of the plastic tappet plate is contacted by the "peg". A common new mistake is to have that peg under the plastic triangle part. It should be positioned so it's about to contact it- when you reassemble the mech box

Yep that how I put the sector gear :s

Is it getting stuck forward or back?

Don't sweat where the nozzle is or if you can push it or not. After every reassembly you should be able to push the nozzle in and have it spring back...but after the first shot it'll be held back some ammount by the post on the sector gear.

If it shoots a BB every time...you've got things mechanically assembled correctly.

If you're getting inconsistent velocities, you've got either an air leak somewhere or an inconsistent air seal somewhere. Usually it's between the tip of the nozzle and hopup rubber, but it can be from o-ring around the piston head too, or from a poor fit between the nozzle and the cylinder head nozzle. If you took the cylinder head off and nicked the oring around it when you put it back into the cylinder...then that could be a problem too. Many hopup units have a spring that pushes the hopup unit back against the mechbox to keep a good seal. If the hopup unit is not seating right up against the mechbox shell or if it's bouncing around randomly you'll get odd velocities. Etc...

Anyways...search for "compression test" and "air leak"...there's lots of threads about it.

Also...tightening things down too much can cause the parts to be pulled out of alignment. These things are all that stiff/robust. Sometimes cranking the screws of the grip on too much will skew things...same with the rear stock screw (on M4's). Try assembling things snug but not tight and retest.

Good luck

back

now it shoots a couple of times and it stops working :(((((((((((((((((((((((((

I also recommend watching a ton of YouTube.

You should kick back , get some snacks, and watch like 5 hours of Echo1Techsupport videos on YouTube, Brian Holt's channel. He does tons of takedowns. After you watch a few of those you will get a sense of what you are supposed to check from front to back, inside out , before and after disassembly/assembly.

Don't listen to anyone who tells you not to open your gearbox. If you keep at it you'll learn something and the anxiety about opening gearboxes will go away. Worth it every time :)

I agree with MaciekA.

If you find some proper resources, it will be a slightly stressful but rewarding ordeal.

It also helps to have an extra set of eyes and hands to help you get the gearbox back together the first time. After the first time, you kind of get a handle on the technique you should use and exactly where each part goes.

Good luck!