So, I've had a problem with my 064 AV the last few times out. Runs great for five or ten minutes, then starts to die. Keeps stalling out between cuts, and eventually gets to a point where I can't restart it. No decompression valve on this monster, so restarting a dozen times over is not a minor detail, either. Suspecting it might be a fuel pick-up issue, I noticed it was always happening when I had used maybe 1/2 the tank of gas. I had it in my head it must be a crack in the fuel pick-up hose, but then today noticed the tank makes a hiss sound when I unscrew the lid. So, when it stalled today, I simply loosened the lid and retightened, and voila! She ran fine again. Seems I have a problem with pulling a vacuum on the tank, and no make-up air can get in. Who knows where they hide the breather on these tanks? I'm assuming a sintered bronze, like they used on older saws, or has the technology changed?