25 liters put in 500 ml oil, 20 liters put in 400 ml oil, or 5 gallons which is 22.7 liters put in 16 oz. 25 liters is not 5 gallons neither is 20 liters. alot of guys with boats always through in 500 to 5 gallon which is not a true 50 to one. just my 2 cents. more oil is not better. if you put more oil remember less gas is going through the main jet which is makeing a leaner fuel mixture. mix it right.