RE: Club FOX!
Don't throw it away....send it to me!
First off...the need to open the LS needle excessively says that there's either a restriction (pinch) in the fuel line, or...an air leak which is limiting the engines ability to draw fuel.
The "leaning out" and overheating is further evidence that this thing isn't getting enough fuel.
It's easier to diagnose these sorts of problems outside the plane, and on a test stand. If you have one....set it up with a KNOWN GOOD tank & plumbing and give it a try. Not with another tank crammed into the plane, because that's where these problems often originate. Get everything in the open so you can see what's going on.
If under these circumstance you're having the same basic problem, then there's likely a leak at the engine. The .15BB has not only a flange mount for the carb, but there's also another point right at the base of the carb body (see the allen head set screw up under there?) that could leak.
Check the backplate screws....make sure they're all tight.
The fuel is marginal for this motor, but should work. I'd add a few ounces of castor to that Omega to bring it up to 20% total oil.
Just an added note: Make sure you're not trying to run a LONG idle bar plug with this engine.
Let us know.