Charging And Starting Systems

My 1989 Ford Bronco II (315,000 miles) smells rich on gas but doesn't show it on the gas gauge. When the truck is running, the exhaust smells like s*@t. I was told to try a new thermostat because I have one in there that runs cooler, possibly not letting the engine warm up to factory temp (195F) and the exhaust fumes seem to never go away even after warm(in the winter). This has been going on for a few months now. Also, when I start the truck from cold, it starts up right away. If I drive it across town, shut it off, then back on, it hesitates to run making me have to crank the starter longer. When the truck finally starts, it sounds like it is missing and smells somewhat flooded, then the idle smooths out. Any suggestions?? Thanks