Hi all I picked up a very inexpensive Snapper Rider. It's small, 25" cutting deck, but it's a really fun machine and the smaller size is easy to get in to smaller spaces and it turns on a dime. It's an older unit and the 6 HP Tecumseh was a POS, and I can't get parts for it anymore, so I picked up a used 12 HP Briggs motor for about $200. I have this problem where the engine will start great when cold, run for about 30 to 60 seconds. Then the governor will take over and start adjusting the throttle, engine RPMs will drop and eventually the motor will cut out. The carburetor that was on there would leak fuel, even with a new carb kit, so I replaced the carb. I've also replaced the ignition coil, spark plug, and re-wired the starter. What I have not done is hook up the alternator to the battery, which shouldn't make a difference other than recharging the battery. I also have not replaced the air filter, which seems a little too obvious. I'm going to replace the air filter tomorrow, but I wonder if there is something else that I should consider. The engine does get hot fairly quickly and that is when it shuts off. Thanks PS. The mower cost me $200, $200 for the engine, and $200 for a new carb.