Using this solenoid is easy. First, make sure your engine is turned off. Then, locate the old solenoid on your Mercruiser, Mercury, or Yamaha 4 - Stroke engine. Remove the old one carefully and replace it with this new ARCO solenoid. Connect the wires properly according to the old solenoid's setup. Remember, this product comes with a 12 - month part and labor warranty, but you can't return it to the place you bought it from. If you have any problems, contact the manufacturer right away. For maintenance, check the connections regularly to make sure they're tight and clean. Keep it away from excessive moisture and dirt to make it last longer.