Sprinkler valve help

[Potato Demon]

Hi, I recently purchased an Orbit model 57461 sprinkler valve and I modded it with a blowgun. In the tutorial I was following (same model and everything) I noticed something different about my valve despite the models being the same; on the output side on the valve in the tutorial above the small rectangular hole there was a tube or something but on mine there isn’t. The tutorial said to plug that hole with epoxy and that applying suction to the small tube on top of the valve helps.

When I apply suction to the tube the air is being pulled (I think) from a small hole you can see when looking through the rectangular hole on the output side (the side circled in red). Should I plug the smallest hole (the one that I circled) with hot glue and do a test fire when my cannon (it’s my second pneumatic) is finished?

To help with clarification I took some photos. I made the hole show up by shining my phone light through the small tube in the top of the valve. In all the photos except the one of the tube the top of the valve is facing up. Oh and here’s the link to the tutorial: http://www.thehalls-in-bfe.com/GGDT/lib ... 1_mod.html

[Cthulhu]

I used this exact valve model on my sprinkler valve mortar, I flooded that entire square hole with epoxy to seal it and works very nicely.

[Potato Demon]

Ok, thanks!

[Potato Demon]

There is an air leak but I believe I can fix it. It is a high pitched noise.