Flyfree69,

In one post you are describing many different situations.

When you lean the engine out for maximum speed, you must back out (enrich it back from MAX) by about 300 RPM. If you now put the nose up, it should keep running.
Find the "nose up" peak and enrich 100-150 RPM from there, still with the nose up.

Verify all the fuel lines, inside the tank and outside it, are correctly routed; the clunk must follow the fuel in the tank, as you change the attitude of the model. Verify the clunk is still attached...

The tank center-line must be at the same level as the carburettor spray-bar. Make sure it is so.

The problem with an inverted engine mounting begins and ends with starting (the plug could be drowned in fuel).
Once the engine is running, adjustment is as per any other engine mounting attitude.

If the engine loads up at low RPM, it cannot be too lean, only too rich. YOU CANNOT ADJUST THIS WITH THE MAIN NEEDLE, ONLY WITH THE IDLE NEEDLE. IF YOU TRY TO ADJUST IT WITH THE MAIN NEEDLE, IT WILL BEE TOO LEAN AT FULL THROTTLE.

Air leaks can only make the engine lean out, not load up.


Start from checking all the fuel lines for routing and free movement and then re-adjust your engine completely.