I have looked around and found a couple of tables that give oil to fuel ratios but none of the ones I have found go back to a 1957 Johnson seahorse. The previous owner told me to use a 24:1 ratio. Is this correct? If so how often should I change the plugs? I imagine that this higher ratio would cause to plugs to fowl up faster. <br /><br />Since it is a higher ration I imagine that I am a high amount of oil to the water. Is there some sort of oil that may be a little more environmentally friendly than others?