We just purchased a used 1600 turbo lawn tractor. It runs fine, drives fine, but as soon as the blades engage it's like it can't handle the load. I've tried cutting thin, dry grass and the engine sounds like it's under huge stress. We've tried testing the turbo and that appears to be working. But honestly we've never been able to engage the turbo because the whole machine dies whenever you try to cut anything. Just changed the hydraulic filter, it has plenty of fluid, changed the fuel filter and oil filter. We even took of the belt for the main deck and it still can't handle the load. Anybody out there got any ideas?