I have a 25hp kohler gdlt on the back of a 1542 war eagle. The motor has been a strong running motor, but is starting to cut out. The motor will run fine at half throttle, but when you open her up she sputters and cuts out. This is with any load. I recently had the carbs cleaned and had it tuned up. Any reason why it will run all day long at half throttle and then when I open it up it starts to sputter then cuts out? Its never done this until recently.
Thanks.

Sounds like either trash in your carb or an air leak in your fuel line.