Yes, I just caught that. Ok, this is conventional and does not have speed control. Speed is controlled by the throttle. The smoke output responds to track voltage. Normally PS-1 engines can run at low voltage settings so the smoke unit doesn't get as much voltage. In neutral are you raising track voltage?
I would try changing wick and run it to see if that improves it. Normally a PS-1 can put out good smoke. G