I've got a 1980 75 hp 'rude. For a while I wasn't able to find gallons of oil and the gas station I've been filling up at only had quarts of non TCW-3 oil. I've noticed problems with idling and starting since I've used that oil. I just got a gallon of my usual TCW 3 oil, so that part is solved. My question is has the non TWC 3 oil done anything other than probably dirty up my plugs? I ran the tank almost empty last trip, so when I get home it's getting new plugs and a couple of bottles of seafoam in a fresh tank of fuel with my usual TCW 3 oil. Carbs were just rebuilt last year and the only other thing I can think of other than the oil is it's possible I need to change the water filter in my fuel line since I've put more hours on that motor this summer than the last two years put together. Thanks in advance for your help!