ICS M4A1 Full Auto in Semi When Battery Low

[dpvu]

Hey guys,

I just want to know if this is normal or if I should get this looked at. Sometimes I'll fire off a few shots in full auto in my basement and I'll switch to semi to fire off a few rounds but my ICS M4A1 continues to fire in full auto. I find this only happens on dying batteries as pretty soon the battery doesn't even have enough power to cycle the gearbox (I just get a partial cycle and it seizes up and I have to use the forward assist spring tension release).

[HaZarD SFD]

its your selector having issues.. not your battery.. contacts make your rifle shoot full auto or semi..

[Renegade)]

Make sure your cut off lever is moving freely, then you will have to shave off a bit of the selector plate, the part of it that makes contact with the cut off lever.. I found the plate was hitting the lever to early and pulling the lever away from the nub on the sector gear that hits it... Took atlot of studying my ICS one night, but after I made that modification, never a semi issue again.

[dpvu]

Hmmm... I just had the problem again and slapped a new battery in there and the problem was instantly solved again. I'm not sure if it has something to do with the gearbox not being able to make a full cycle under a low battery and becoming stuck on full auto. Either way, I know I need new batteries. I'm going to invest in some batteries that don't suck (I'm using 2 cheap 600mAh batteries that I got with the gun) and see if that helps at all.

[Sniper Steve]

This is most likely the selector plate or the Cut off lever. About a month ago I had the same problem with my ICS M4. It turned out to be a broken cut-off lever.

I doubt it is the selector plate because all the selector plate does differently from semi to auto is move the cut off lever away from the cam on the selector gear. So, unless the small spring is detached and the selector plate is jammed in the up position the selector plate is not broken.

The most probable cause for malfunction is the cut off lever being broken at the tip where it interacts with the gear box switch assembly.

Just to confirm... Does the rifle successfully engage the safety when you put the fire selector on safe? If so your selector plate is moving properly. If not then the fire selector plate is stuck on auto and there is a problem with the fire selector or the selcetor plate.

Move Info will help me diagnose the problem further. It sounds like less than 10 dollars of part though. (Cut off lever is $6 + shipping from eHobby)

[dpvu]

That's good to hear that it's a cheap part if anything. The safety is working fine (locks the trigger). I did find that I can stop it from happening most times if I go all the way to safe from auto, push the spring tension release then go to semi. If it is the cut off lever, how hard is this part to replace? I've never dug through a gearbox before. There's ICS M4 gearbox assembly/disassembly videos on YouTube but I'm still not sure I want to open it up myself.

[Sniper Steve]

Well if it does go to semi-auto some times then it may not be a broken cut-off lever but rather the lever is not able to move freely. Its hard to tell without seeing it but if the rifle engages the safety fine and fires full-auto then the selector plate and fire selector switch are fine.

About opening the mechbox. Are you mechanically inclined? Have you worked on engines or electronics or anything like that? The mech box is not really that complicated. The only tricky thing is timing the gears. But if your good you can change the cut-off lever without having to time the gears if you take it apart right. (Assuming that is the problem) If you do take it apart make sure you take note of what goes where and how it is placed.

Where are you located?

If your are able to actually acheive semi then there is most likely something wrong with the spring that connects the selector plate to the cut-off lever or the cut-off lever is having trouble moving freely.

What is the nature of the gun? Is it brand new ish? As in are you the first owner? Has it had any upgrades? Such as a steel upgrade cut-off lever? The reason I ask is that I needed to sand a bit of the inside of the hole that the cut-off lever rotates on from the replacement I bought. The reason was that the cut-off lever did not rotate properly and this would have caused problems engaging semi-auto.

[dpvu]

I'm in Calgary (should probably get that in my profile). I'm pretty mechanically inclined, I do lots of soldering and fixing electronic things that break a lot but never anything with gears and such.

I'm the gun's second owner, it's about 2 years old but wasn't fielded very much by its first owner (only a few times indoors). All the internals are stock and the original owner said he never even touched the mech box.

[Sniper Steve]

Ok, well electronics and wiring are a bit different than gears and what not but alot of the thinking involved is the same. Was the semi-auto working before or did it not shoot semi at all when you bought it. Did it slowly phase into not shooting semi? IE, did it ever randomly shoot full auto in semi? The reason I ask is that the rifle is 2 years old. This means that the mechbox switch assembly maybe worn out where it interacts with the cut-off lever and as a result the cut-off lever is not able to open the switch and stop electricity from going to the motor. (ICS switch assemblies use very soft plastic compared to the other companies) Either way the fix will be in exspensive.

[dpvu]

To my knowledge it did this when I got it. It's always been capable of semi, this glitch just happens when I go auto to semi on a low battery. I usually shoot semi in my basement but for fun I'd play around with auto and the first time it happened it scared the crap out of me but I knew the battery was dying and I swapped a fresh one in and everything went back to normal. It's happened a few more times (all on dying batteries).

[Sniper Steve]

Ok, wow thats really weird how the battery affects that... I'll think it through and come up with a solution soon. Do you switch the rifle to safe when switching batteries?

[dpvu]

I'm pretty conscious about switching the gun to safe whenever I'm not actually firing so it should be in safe when I switch batteries unless I had a lapse sometime.

Thanks for all your help. It's not a huge issue. I'm still thinking it's something to do with the gearbox not cycling all the way in full due to a low battery and somehow that keeping it in full auto with a low battery but I don't know enough about the inner-workings so that's just a guess. Either way it's not a gun-crippling issue, more of a small annoyance I'd like to get fixed for safety reasons and to stop the problem from getting to big.