Small Engines (Lawn Mowers, etc.): riding lawnmower exaust, lean mixture, exhaust temperature

Question
what is causing my exaust to get real red and hot?

Answer
This is generally caused by an excessively lean mixture from the carb.  The high speed mixture screw should have an initial setting of 1 1/2 turns out from lightly seated.  Then you should adjust in (CW) until the engine starts to surge.  Then open it back up 1/4 of a turn.  This should be sufficiently rich to provide good power and also lower your exhaust temperature.  If a carb adjustment doesn't correct, it will need to be cleaned thoroughly.  Hope this helps.