Hi Jedda,
Thanks for the tip for the crazy nut cooling head!
My settins were; 4 turns out on the HSN and 1/3 turn from flush on the LSN.
After writing my last post, I went out to the track to feed the monster some more fuel....
And a little miracle happened -> for the first time temp stayed below 285 F / 140 C.
Fitting a new glow plug (Cen R3 instead of the original N3) gave a much better iddle but not much difference in engine temp.
Emptied 3 tanks and tryed to lean it out a bit (1/8 turn).....oeps.....again temp up a bit but also a noticable improvement in accelleration!
And another day at the track went by without any damage to the Genesis! (and I did make some big jumps!)

To Benifur;
I had the same problem with the steering (big radius one side and even bigger other side).
Because I also experienced some radio glitches (there are some high power electric cables under the parking lot of a football stadium where we race) and found the dual rate and trim controls on the Cen radio unusable, I put in a receiver for my Futaba 3PK.
Now I could easily set EPA etc and had a turning circle of 4 feet!
Also servo respons improved dramaticly. Together with the 6 Volt Nicad receiver pack I believe -for now- that the steering servo is -just- powerfull enough for the job.