E-Mag valve issues - trigger resetting slowly

[armymanadam]

Hey everyone, I'm new to this forum and Mags in general. I recently bought a classic Automag with E-Mag valve, Level 10 bolt and RT on-off. I've fixed a few issues with it by replacing the power tube o-ring and properly adjusting the Level 10 (previously the bolt was sticking badly). I also replaced the bolt spring with one direct from AGD (part #798).

I'm still having one more issue though. Even though the bolt appears to be resetting all the way, the trigger takes 1-2 seconds to reset each time I fire. Nothing is leaking at the moment, and if I wait for the trigger to reset, it does seem to fire correctly. It almost seems like the on-off pin is sticking, but I don't know for sure.

I did quite a few searches here and on other forums, but I couldn't find anything helpful for this. I do believe my Level 10 is adjusted correctly, because I'm using the largest carrier size that does not result in power tube leakage.

I'm using a standard fixed-output HPA tank that puts out somewhere around 800-850 psi. I've heard that this should be enough for the gun to cycle properly.

One other thing I should mention is that some of the urethane o-rings in the valve and bolt appear to be slightly swollen and brown, so I'm wondering if the previous owner used some kind of lube in the gun that swells o-rings in order to fix a leak. If that is the case, I wonder what other o-rings I might need to replace so that the gun cycles properly.

[Cyco-Dude]

urethane o-rings will slowly turn brown over time, so it may be getting close to a rebuild.

as for the bolt being slow to reset, you can try putting the carrier o-ring into the next largest carrier and test it again. or, just use the hell out of it and it should fix itself as the o-ring breaks in. make sure that o-ring is lubed.

[armymanadam]

I took the valve apart again and took a closer look at the o-rings. I compared the o-rings there with the parts diagrams online and discovered that the previous owner had used the wrong size o-ring for the valve seat (it was too small). I replaced it with a new, correct size o-ring and put everything back together. However, the gun's behavior after making this change was exactly the same, strangely enough.

I tried turning up the velocity in case this is just an issue of the gun not having enough pressure to push down on the on-off pin. I turned in the velocity screw until it bottomed out and then backed it out about 1 full turn. Now the gun won't cycle at all--the bolt acts as if there is an obstruction in the breech. I will try the next size larger carrier to see if this helps.

I also have a classic valve laying around that I will try testing some things with. I may try the Level 10 bolt on the classic valve and the older bolt on the Emag valve just to see what the behavior is.

[Cyco-Dude]

you might have turned the velocity too low. when i assemble a reactive valve, i'll just screw in the reg adjustment nut to where that line is hidden. then gas up, and start increasing velocity while firing until the valves cycles reliably. usually it's done over a chrono so i can set it up and make sure it's doing what it's supposed to.

i actually had a similar "problem" recently; i installed a level 10 bolt onto a minimag valve. when i went to test-fire, it just chuffed and reset. level 10 bolts require higher velocity than level 7 bolts to operate, and i had forget to turn the velocity up. lol!

[zondo]

Wonder if your reg piston needs to be replaced.

Also, make sure you're using a quad o-ring for your on/off pin.

[armymanadam]

Wonder if your reg piston needs to be replaced.

Are you talking about the whole reg piston or just the reg piston o-ring?

[captian pinky]

Wonder if your reg piston needs to be replaced.

Also, make sure you're using a quad o-ring for your on/off pin.

you only use a quad oring with a .712 rt pin.

[athomas]

A slow resetting trigger or on-off is a normal symptom of bolt stick. The on-off not resetting, is an indication that there is not enough stick to prevent firing, but there is still too much stick to allow a proper reset.

A leaking on-off oring could cause problems as well, but most of the time it is the carrier size. If the next larger carrier size causes a leak, try a new oring in the carrier and go through the tuning process again. Sometimes, you just get an oring that has a flaw that allows a tiny leak under normal circumstances, and causes you to use a carrier size that is too tight to prevent that leak. Always remember to tune without any powertube shims installed. You don't need them, and they can cause leaks that will make you use a carrier that is too tight.

[Justus]

A slow resetting trigger or on-off is a normal symptom of bolt stick. The on-off not resetting, is an indication that there is not enough stick to prevent firing, but there is still too much stick to allow a proper reset.

A leaking on-off oring could cause problems as well, but most of the time it is the carrier size. If the next larger carrier size causes a leak, try a new oring in the carrier and go through the tuning process again. Sometimes, you just get an oring that has a flaw that allows a tiny leak under normal circumstances, and causes you to use a carrier size that is too tight to prevent that leak. Always remember to tune without any powertube shims installed. You don't need them, and they can cause leaks that will make you use a carrier that is too tight.

This, exactly. I ran into this same problem several years ago and after a lot of frustration and diagnosing, athomas told me this. So I threw the carrier o-ring out, got a new one, and retuned the L10. Everything worked perfectly after that. It was a perfectly good o-ring, just one of those 1 in a thousand that won't work with the carriers because it's an "in-betweener" in sizing.

It's probably the most frustrating L10 tuning issue, to me anyway, because it's hard to diagnose and then you feel like you're just tossing out a part that should be perfectly fine.

[armymanadam]

Thanks for that info! I tried the next larger carrier several times with the same o-ring and kept getting a leak, so I just assumed that I was using the correct carrier. I will try a different o-ring in the smaller carrier as soon as I get a chance. I have about 6-7 other new ones to choose from so maybe I will get lucky!

As for other testing, I did seem to have some success after using the correct spring length (appears to be the gold spring) and also after replacing the small on-off o-ring and one of the small reg piston o-rings. The gun was just starting to cycle and recharge mostly correctly...until of course my tank ran out of air :).

Since my tank is empty, I took the opportunity to add an additional shim inside the tank reg to get my output pressure a little higher (should now be in the 800-850 range). I'm hoping this will help rule that out as being the issue. I'll post another update once I've tested again.

Thanks again for all your help! I've really enjoyed my time on this forum so far.

[armymanadam]

Hey all, just wanted to post a quick follow-up for those who are curious. I just got my tank refilled and tested my gun one last time. It's now cycling great! Here is a recap of all the things I had to do:

--Switched to gold bolt spring
--Replaced a bunch of old, swollen o-rings in the regulator and on-off.
--Tried a different carrier o-ring (not too tight, not too loose)
--Replaced reg seat o-ring with correct size
--Upped the output pressure of my tank to 800-850
--Turned up the velocity

I still have only dry-fired the gun, so we'll have to see what other adjustments are necessary after I can fire it over a chronograph. However, the most important thing is that the gun is now able to keep up with my trigger finger, and I no longer get any chuffing or bolt stick!

[athomas]

I was going to mention the filled tank issue. If you happen to be operating on low tank pressure, some of the orings don't seal properly right away as the gun cycles. It can cause some lag in operation due to sticking caused by air leaking past the orings. I dismissed it because you were originally having the issues with a filled tank as well. I guess it just goes to show that all things should be mentioned, no matter how trivial. Its good to hear that it is working now.