Pictures would help. Is there only one adjustable needle? Could you not turn the needle at all, or was there and additional screw related to the needle that wouldn't move? Does the needle screw through that "rubber looking thing", like it is a washer, and is there a compression spring in between the underside of the needle thread and the rubber? Re-adjustment usually amounts to screwing the needle out a lot, so the engine will run rich and start. Once it is running and warmed up you start moving the needle and just see how the engine revs up when your snap the throttle open and takes a load in normal service. If there are two needles, then one will be for idle and that is adjusted for most stable idle. Same for the stop screw on the throttle shaft, if there is one. One problem I often run into on the very cheapest carbs is that the throttle is just a die-cast "plug valve" rotating in the die-cast carb body and wears so bad there is a lot of looseness and flopping around. Since that is after the carb throat and fuel metering, the mixture reaching the engine is out of "original" calibration and is varying at random! Hopefully, yours is a larger "small engine" with a more sophisticated carb. Again, pictures would help. If you have trouble posting them, PM me and we will work out a way.