Hey guys looking to find out how to keep my motor in tip top shape , I recently bought a 2000 nitro 700 with a 75hp tracker motor by mercury marine and want to know why it smoke will idling and when idling it kind of runs a litttle rough what do u guys recommend me put in the gas. Also need to know how to check oil that is in the lower motor unit there is 2 screws towards bottom of motor , one reads vent other says oil level ??