They wouldn't have put that big, slotted adjustment screw on the regulator if it was not meant to be adjusted. 1/8 turn will do little to solve the problem.

Part of your problem is fuel. YS engines idle and transition poorly on anything less than 20% nitro, and we prefer 30% heli fuel in the 63, so change fuel.

Then go to www.ysperformance.com and follow the running instructions.

Let me know how it works out.