Adding Marine PRO to 2 cycle oil [SOLVED] Asked by Roy S. In Arkansas Would it be ok to add Marine PRO to 1 gallon of new 2 cycle oil before adding to oil tank? I have a 1997 Yamaha 150 hp .
Good question, Roy. Yes, you can add Marine PRO to oil. Add 1 oz of Marine PRO for each quart of oil (so in this case, 4 oz.).