Surging most likely means the carb needs cleaned. As far as not rolling in neutral, Possibly the parking brake is sticking in the on position, but that usually will also prevent driving, unless it is unsticking when the force of the tranny overrides the resistance of the brake. brake lever is located on the right side of the tranny in front of the axle. If it is sticking you will hear a click when you move the brake lever on the tranny with your hand.