I just bought a house in the country that came with a 2014 L3200. I see the red handle on the back for "oil" but how do you check how much is in there and what is the preferred weight should you need to add? If I brsuh hog for about an hour, it will suddenly lose power to the point it limps back to the shop. Any suggestions would be appreciated. I am handy with a wrench but literally no experience with a tractor.