Diaphram gets stuck down (modded sprinkler valve)

[Ublind]

I created a pneumatic spudgun with a 3/4 in. LawnGenie sprinkler valve on it (with guide rod.) Because of the guide rod, I inserted the blowgun beside the guide rod, which was on the edge of the innermost hole. My gun worked perfectly until recently, shooting the handle of a shovel through 1 in wood! Now everytime I shoot the diaphragm gets stuck down, so the air just leaks by it until I open up the valve, unstick the diaphragm, and reassemble the darned thing. Can anyone help me with this problem? Can I just remove the guide rod?

[clemsonguy1125]

Don't remove the guide rod, did you lose the spring at any point?

[Ublind]

The spring is still on and I tried stretching it out so it pushes more on the phram, but no dice. My first gun, BTW.

EDIT: I'm out for the night, i'll check back tomorrow

[hi]

You might try just a little bit of grease. I have only worked with valves without a valve guide, but to me it sounds like a bit of bearing/lithium grease work work well.

[Hubb]

You might try just a little bit of grease. I have only worked with valves without a valve guide, but to me it sounds like a bit of bearing/lithium grease work work well.

I was going to suggest cleaning it as well. Also, make sure that the spring is not binding up when it is being fired.

[Pyro Ninja]

I had the same problem with the diaphragm not reseating properly and constantly had to open the valve and reseat the diaphragm manually.

I found out that the bottom of the diaphragm was catching on a tiny lip where it seats, so I sanded the lip off and smoothed it over with a fine grit abrasive paper. After I removed the lip it worked consistently well.

And yes, don't remove the guide rod as than the equalisation hole will be too large.

[Ublind]

I already put some grease on it, so I cleaned the diaphram and stretched out the spring so more pressure is pushing up on the phram and now it works like a charm! Thanks for your help!