Bought mower that was suppose to have carb problems ... Would start and idle fine but with a little more throttle it would start popping and sorta backfiring through carb so bought new carb... Same problem ... So I adjusted valves ... Still same thing .. I bought new head and installed it... Same problem.... I have adjusted carb in all ways possible and checked flywheel key ... I am stunned need help

Was hoping there would be someone on here with Tuff Torq or hydro trans experience. I have replaced the motor,pump and center case. I also replaced all the bearings in this unit too. Thought this thing would be long gone and out of my shop months ago but I keep pushing it to the back of the shop. The trans seems to make a howl type grinding noise only when going forward. The forward speed seems slow too. It will not climb a hill at all either. Stops at the base of the hill and the grinding noise really gets severe when trying to climb. The reverse on the trans is fine. Speedy,responsive and quiet. Was wondering if anyone out there that has experience could shoot me some ideas. I am way into it money wise so I don't really want to abandon it. Cheese, I know you said before your experience with these isnt great. Do you know of anyone that has experience with them I could email? thanks