Piston getting stuck in the back of gearbox b4 releasing

[gerardcb]

Hi!

I have this echo 1 m4.

When I fire the gun, the piston gets stuck in the back of the gearbox before releasing.

Everytime I do this, I have to open up the gearbox and have the piston shoot forward to the front of the gearbox then try out a new solution.

I have tried replacing out the piston, thinking that the piston might have not fit the shell.

I have tried replacing the gears just because.

I tried a loose shim job, a tight shim job, and the correct shim job. The shim job is good so that should not be a problem.

I tried replacing the cylinder and cylinder head.

I tried using the stock motor, a systema magnum motor, and a G&P M160 motor. With all of them, the piston gets stuck in the back.

I'm only using an m120 spring.

I am using a fully charged 9.6v battery.

What else is there that could be the problem?

[Thenooblord]

motor could be too weak, or battery
what spring you running?

[Styrak]

Most likely a not powerful enough battery.

[sushicake]

Either your batteries too weak or your springs to strong for the motor to pull or the piston isn't sitting right on the rails cause it to jam.

[gerardcb]

I am running an m120 spring only. The battery is a fully charged 9.6. I tried a systema magnum motor, a g&p m160 motor, and the stock motor. All the same results.

[Thenooblord]

fully charged battery may be true, but the cells themselves could have died or been damaged, how old is the battery? has it ever shorted? been overcharged/completely drained?

[Eldin]

I had the same problem a few days ago when I was working on a friend's SRC M4, I just switched out the spring guides and the problem was resolved.

[Styrak]

Originally Posted by gerardcb

I am running an m120 spring only. The battery is a fully charged 9.6. I tried a systema magnum motor, a g&p m160 motor, and the stock motor. All the same results.

That doesn't really tell us anything. Is it a MINI or a LARGE battery. That makes a big difference.

Also, try another battery.

[Kos-Mos]

Try a manual test.

Remove everything but the piston from the mechbox (trigger parts are ok).
Close the shell with the screw as if it was complete.
Push the piston all the way back with your finger using the cylinder opening.

If it jams, it means the mechbox shell is poorly made and the rails contact the piston too much... You can try to find out where and sand it down, but it is a long and touchy job to do... remove too much or from the wrong spot and your piston will jam and strip.

If it is ok, add the spring guide only and try again. Some bearing spring guides have bearings that are a tad bit too large and hold the piston in place.

[Drake]

Are you using a spring guide w/ brearing? Piston head w/ bearing?

[gerardcb]

thanks everyone =)

im using a spring guide without a bearing and a piston head with bearings. But Ive tried different set ups, so that should be the issue