I recently had a situation on my Moki 1.8 glow where after buring a half tank the engine would go lean on uplines and want to flame out if I didn't come out of the power.
I found a very slight crack in the mold line near the rubber stopper that would weep the fuel out (barely)when full (no chance to lose tank pressure) but then begin sucking air at some point where the flame outs woud occurr or want to.
I am not saying it will fix your problem, just FYI info while you are troubleshooting. This fuel tank is only 3 inches from the needle valve and it runs flawlessly now.