hello have a Beaver 3 and I I don't think I ever found the oil dipstick. I searched all over the engine compartment and nothing. The manual says nothing. I changed it once and I've been just topping it off every once in a while for years. I may have known way back then where it is but I have CRS disease. It's making a hard to hear slight knocking since I drug it out to move 12 yards of gravel. I did put half a bottle in but I have no idea if that's enough. Can you tell looking at the engine through the filler cap?