My ST90 worked like a charm for about 3 month. After the last time I flew, I cleaned the engine and it has sat there in the garage for about 2 months. I started it today and it started right up. We then took it to the field where we noticed that it sputtered when accellerating quickly. I was unable to adjust the needle valve so as to fix the problem What are the steps I need to take to get it running great again? I appreciate your help.

Best regards

Gene