Need help and fast...
 

This is a problem encountered on 3 different engines on three different people up to now and we don't know what's causing it.
We are not noobs on tuning so we know the "basics".
Engine runs fine with the glow starter on but dies when removed and give it a full throttle.
If it's a blip style full throttle it will die while going to idle.
If it's a WOT to clear the engine it dies before reaching full rpm by dropping rpm and dying.

We all run RB 30% buggy fuel.
Engines are 2x RB WS9 and one Reedy 121VR.
We tried tuning it...no success.
Tried different plugs...nothing.
Tried other engines on the same car and they work...so it's not the fuel tank, clutch or pipe.

Any suggestions would be appreciated.