Does this machine feel like it is going to flip over backward at any moment to anyone?? I have one that i am using and it is very tippy feeling. Does it take a lot to tip this thing? how far backward CAN it go? will the engine cover stop it from tipping? i'm not on anything crazy by any means, but if you run over a rock the damn thing feels like it's going over. I was moving gravel with it and it constantly only had a couple of wheels on the ground.