I've got a f620 with a kohler 20hp Vtwin. Something flew apart in the engine while the wife was mowing this weekend. I priced a short block from JD, it was $940. From the sounds of the engine it's in the bottom end. It'll still run but low power and noisey (rod noise). My questions are: is it worth trying to rebuild this motor or are the cost of parts going to make me cry? Is there another option for an engine, maybe something with a few more HP? If I'm going to drop a grand on a short block I wouldn't mind sending a bit more to have a nicer engine. Any help would be appreciated.