I have a major leak! First it was leaking out my expansion chamber. I fixed that. Then my gun wouldn't cock. I read another thread and fixed that. Now its leaking out my barrel. I checked my valve and couldn't see anything wrong. I checked my cup seal and couldn't tell. I know I don't have that star guide washer thing. I just got my F4 from my friend and I know just about nothing about F4's so help me please!!!
Uhm, that star-shaped washer thing is pretty important when it comes to making sure your cup seal aligns properly with your valve. You may want to seriously consider buying a replacement part from ACI (www.airconcepts.com) - goto their online store.
"Good? Bad? I'm the guy with the gun..."
I had that problem once, I did a thurough cleaning, I took off the the low pressure chamber or button, made sure that everything was fitting correctly, I cleaned the orings with alcohol let them dry and then lightly oil them as your putting thing back together. I did this for the lp chamber, asa line,velocity chamber, bolt chamber and bolt. Clean well lightly oil as you put things back together. Visualize and make sure that that things are going back as they should.