My neighbor got me feeling guilty that I hadn't been adding a stabilizer to my deisel fuel so I went out and bought Sta-bil (red fluid in plastic bottle). I added it to all by gas engines and didn't think it would hurt to add the appropriate amount that went with 5 gallons of diesel to my tractor. I mixed it in the diesel can and poured into tractor to get a full tank. I went to my small engine repair class and he said you don't add that to diesel. Should I drain it out now or will the one mixing not hurt it? How is the best way to drain it? I can't seem to locate the manual right now. Is there a drain plug below somewhere for easy draining? Thoughts/advice from smarter, knowledgeable, tractor folks would be much appreciated. Thanks