I have a craftsman pressure washer I bought back in 19. Has the Briggs engine and says no oil change needed ever, just checking and add. I figure this year I would go against their advice and change it anyway. No drain plug to be found. How do I drain the oil out?.was thinking of draining the gas and just tipping it over and draining it. Also can’t remember the oil type and can’t find the manual would it be SAE 30?