I have a Transmatic Lawn Tractor, Model 660-679,42", 14HP. When I gently or otherwise engage the mower deck the engine stalls out. The spindles on the mower deck turn freely by hand and there is no binding. The deck is level as merasured from the ground. The tractor pulls a loaded cart without trouble and freely runs in the yard at all speeds. What do you suggest is the problem. My email is wsnyder@northwood.com Thanks.