Most ZTR or Zero Turn Lawn Mowers have a twin cylinder engine. The standard manufactures are Briggs and Stratton, Honda, Kohler and Kawasaki. These engines are fairly reliable for the most part, but sometimes can have their problems.
A loss of power on your zero turn can happen when it is brand new or has a 1,000 hours on it. I worked on a fairly new one that had a piece of plastic come from inside the fuel filter and end up in the carburetor and blocked off one of the main jets. It ran fine at idle, but when you turned on the PTO, it would bog down and practically die.
Usually in cases like this, one cylinder is down on power and may not be getting enough fuel, compression or spark. Each of these systems will need to be tested to find out what the problem actually is.
Turn the engine over a couple of times and then shut it down. Pull both spark plugs and see which one is dry and which one is wet with fuel. If a spark plug is dry, fuel may not be getting to that cylinder. If one plug is really wet, spark might not be getting to that cylinder.
Other things can happen like the valves become out of adjustment and a cylinder head push rod will come off and not allow a valve to open.
You want to systematically determine what is causing this problem and then replace or repair the parts and test it again.
If you need expert care for your Zero Turn lawn mower that has lost power, visit our Locations page for help.