My 1969 150J uses 1/2 qt. every 5 hours. I also am a firm believer in MMO in the fuel every 4th top off. 1/4th pt.in each tank. and a pint in the oil at oil change. Oil is changed every 25 hours. My engine is high time and no oil leaks, has strong compressions and no metal in the filter and the oil samples are normal..
