What is the oil to gas ratio amount for a 1992 Yamaha 25hp boat engine?
The oil to gas ratio for a 1992 Yamaha 25hp boat engine is 50:1. This means that for every 50 parts of gasoline, you should add 1 part of oil. For example, if you are adding 10 gallons of gasoline to your boat, you should add 1/5 of a gallon of oil.