tuning

[Dickylew]

hi all, got a Hobao Hyper 7 black around xmas time and need advice on tuning the engine.

Ive started to lean it out a bit but after running about 5 minutes the engine cuts out.
I notice at the top of the glow its fizzing with fuel slightly and the engine seems to be a bit lumpy but not too bad at full throttle.

Would this indicate that it is running too rich?

Where should i start? leaning the main throttle or the low speed throttle first, bit concerned as im still learning and dont want to risk overheating the engine by running too lean.

Any advice would be appreciated.