Troy-Bilt Horse rototiller is a dangerous machine
The trouble is the design. The rubber belt contracts when it heats up (rubber is an unusual material in that it contracts instead of expands when it gets hot), as a result it gets too tight and makes it hard to shift into neutral. I have had my rototiller get away from me many times when I came close to a bush or fence and couldn't get it into neutral to shift to reverse. This is especially dangerous on a hill made of hard clay like I have. The tines can propel the rototiller forward in high speed surges when they hit a hard spot. In fact I am bleeding right now from the latest episode where the rototiller ran into my Kumquat bush.
And don't say I don't have it adjusted right. I live on a hill and when tilling uphill the belt has to be fairly tight or it just slips and the rototiller won't move. If I make the belt loose enough so its easy to shift the rotiller won't go uphill under heavy load. If I make it tight enough that it will go uphill then I can't shift into neutral when the machine and belt get hot. Right now my workaround is to only rototill for ten minutes at a time and then let the tiller cool for an hour.
If you have a large lot on level soft ground with plenty of room to make turns you probably don't have these problems. But if you have cramped conditions with lots of obstacles on a hill with hard dirt you know what I am talking about.