V3 gearbox locks up

[tomwo]

I have a recently purchased G&G RK74e with a V3 gearbox that I am running with an 11.1V 25C LiPo. On my first game using it during full auto fire, the gearbox seized up. I could hear the motor attempting to engage the gears but just made a clicking sound on each attempt to fire, until this then blew the fuse. I initially fixed the issue by breaking down the gearbox and reassembling it, and then it worked flawlessly on my next game. During my next game, the gearbox seized again instantly on the first shot. Upon taking the gearbox out of the gun I noticed that the air nozzle and piston was stuck in the cocked position.

I'm really stuck to what could be causing this, it appears that the gears have pulled the piston and spring back and then instantly seized. Can anyone help me with what this problem is and how I could solve it? Thanks

 

[RR01]

First off, is the gearbox rated to take an 11.1V Lipo?  If not, then that may be part of your problem.  Have you tried running it of a 7.4V Lipo?

 

[tomwo]

I would assume so, it's from the G&G advanced range and they specify to use the 11.1 LiPo with their ETU and MOSFET. Can't see them offering that advice and then not building a gearbox to cope with it. From looking inside the gearbox I have identified each part against what's available on the market and it's all high end stuff.