I have a Craftsman LT1000 with a 17.5 hp motor. First off, it runs rough. When it is running it isnt smooth it sounds like little "backfires". And when I turn down the lever to slow the engine down it just dies and will not idle. I believe it may be the carb. I did have to install a fuel shutoff because there was still gas flow into the engine even after the machine was turned off.