I'm not familiar with your tractor model, but I remember reading somewhere that older model tractors with gravity-fed tanks should be parked with the gas tank shut- off valve turned off, even for a short period, and especially for longer periods. Also, the throttle control lever should be kept in the completely off position. It seems that if the tractor is turned off with the throttle lever left open, as well as the gas shut-off valve open, it may allow gas to continue running through the carburetor into the engine and possibly into the crank case. I don't know exactly how this happens, except for the gravity part. I'm a newcomer to tractors, but someone else could explain it better. Like I said, I don't know anything about your tractor model, and this info may be useless to you. I do hope, however, that you can get the answers you need. Blessings to you.