I have recently purchased an 18 ft. deep vee grumman with a 90hp 2 stroke. This engine is equipped with oil injection. How do I know it works? What would be a proper oil mix to run until I know that it IS working properly? The boat has an 18 gal onboard tank. Also the warning buzzer that is supposed to go off when the ignition switch is turned on until proper oil mix is achieved, doesnt seem to work either.