mower won't start when cold but once its hot will start right up.

Hi all,

I purchased a used troy-bilt with Briggs and Stratton 675 motor recently. The previous owner thought is was a 2 cycle engine and was putting mixed fuel in it. Also he overfilled the oil.

Before I bought it I started it. Although it blew white smoke and dripped oil from the muffler it did actually start. I brought it home and drained the fuel, cleaned the carb, and drained some of the oil to the proper level. I also removed the muffler. When I did the thermostat linkage came off. I found a website that explained how to properly install the thermostat so I feel its installed properly.

Here's my issue. The mower won't start when its cold. If I mess with the plastic armature attached to the thermostat and carb spring I can get to start. When the motor is hot it will start right up. Is it possible that the thermostat is bad.

Any advice is appreciated.