ICS M4 firing problem
 

I just got an ICS M4 RIS. I put it together with my old upgrades. Prom 110 sping, Top aluminum piston and head, and TM stock gears. I checked and rechecked my shim job and it seems fine. Now I have no semi auto fire. If someone can help I would greatly appreciate it.

Your going to have to open up your lower gearbox, odds are this part;

http://www.speedytoys.com/shop/item.asp?itemid=540

is either installed incorrectly or broken

I think it might be a broken trigger post. A little nub to the left of the switch assembly, that stops the switch from coming back too far (just above the trigger).

I think there was a thread on this somewhere, with pics

It's pretty hard to intsall the yaw bar incorrectly, but it may be missing the selector spring.

Or it could be that your shim job on the sector gear, coupled with the fact it's a Marui gear may mean it's not properly engaging that yaw bar. This will only affect semi and full auto will still work.

Brand new trigger in it.

That yaw control is in and in correctly. I can see where the nub on the one gear is supposed to hit that but it doesn't. Could it maybe be that the TM gears are not compatible with the ICS gearbox??

Try shimming down the sector gear until it reaches the yaw bar. You'll likely need to re-shim all the other gears and the AR latch as well.

Had this same problem with my ICS, takes very carefull shimming of the sector gear, tight on that yaw bar, as well as corect first placement of the sector when u close the mechs.