1986 LLawnboy (Gilson)with 8 HP Tecumseh and I use Rotella T-6. This blower has HUNDREDS of hard hours on it as up to 2010, I did an entire cul de sac curb to curb and four driveways. Started on the second rope pull this year. I do use MMO in the gas, run Shell 93 octane and always dope the gas with Stabil, run the thing until it runs out of gas when I put it away for the summer months and then put storage fogging oil in the cylider.