Acrylic is a water-based paint, so it will not adhere to plastic. If you’re using spray paint, you’ll want to use something like Krylon Fusion or any Krylon paint that is for plastics. There’s also Plasti-Dip spray paint, and Rustoleum also makes a spray paint that adheres well to plastic. We do recommend washing the whole surface of the motor, heads, etc. with dish soap……this will remove any mold release or other products that may keep the paint from sticking…..a quick wipe down after with rubbing alcohol should help with that as well…..let dry good before applying paint