I'm confident that tank leakage is the culprit. Like I said, I've set everything back to specs and ordered a new Tetra from Central Hobbies. Concerning tank installation, the VF extra 300's wing is installed upside down, so access to the area is inverted. So when you install the tank, it has to be installed upside down. When right side up the tank is actually hanging by the tywraps.
ORIGINAL: sport10
The tank leak is a sign of a high pressure leak which means the tank needs to be replaced. You should be using medium fuel line in this app too so the tubing will properly fit the tees and fuel tank. Always use either an OS F or YS 4 glow plug in this and all other YS fourstroke engines. I am unsure why the tank has to be mounted upside down couldn't it be turned upside down when it is mounted so as to be installed rightside up when the plane is at rest. Resist tuning the regulator unless it is absolutely nessasary.