I have a 3.5 hp briggs classic that im gonna be changing the oil in. I got the mower last year from a church that hadnt used it since 2005. I drained the brown gas and refilled and it started on the 1st pull. I changed the oil probably 4 times since i got it. It burns no oil with straight 30 wieght. the reason im changing it out now is i believe I got fuel in the crankcase. I'd like to get as much life out of it as possible but at the same time dont want to pour a lot of money into it. so the question is which oil (brand and weight) 3 bucks a quart and under would you guys suggest for this beast I'd like to run the oil for this season and next season if I can hold off that long on changing. Im usually good at choosing oil but this time there are just too many to pick from lol. I've thought of quakerstate defy, service pro from ace, and supertech 15w40. thanx in advance guys