P90 Trigger Problem

[Will_0]

I understand that for single shot on the P90 (TM btw) that the trigger is only supposed to be allowed a certain part of the way back. So in other words whilst on single shot the trigger will only go back about half way.

However on my P90 whether it's set to single or full auto the trigger can move all the way back and so I get full auto all the time.

Does anyone know how to fix this? Any help is appreciated