Small Engines (Lawn Mowers, etc.): John Deere 445, radiator cooling fan, john deere 445

Question
QUESTION: I have a John Deere 445 and it runs fine and while mowing the temperature remains normal (just barely off the bottom of the gauge) however when you let it idle, the temp gauge will shoot up and peg within 3 seconds....if you rev it up the temp goes back down.  Any thoughts?

ANSWER: I am assuming you have the liqid cooled engine.  I would start by checking the coolant level followed by checking the filter screens for debris.  Most of the liquid cooled engines have a screen in front of the radiator that requires regular cleaning.

Is the radiator cooling fan working properly?
Let me know.
Eric

---------- FOLLOW-UP ----------

QUESTION: Eric,
Yes I had recently flushed the coolant and replaced with 50/50 mix.  I had also took my hose and sprayed clean the radiator and both sides.  The fan is connected to one side of the crank and runs all the time the mower runs.  On another note this whole thing started after I was having problems getting it started.  I could crank it for hours and nothing.  I changed the gas and put sea foam in it and it finally started.  I mowed tonight for 2 hours, then let it cool and now I can't get it started again.  Are they related?  Or am I missing something?

Answer
Have you replaced the spark plugs?  Did the mower sit for a while or did you possibly have some bad fuel that got in the fuel system?  Do you have spark?  Is the thermostat malfunctioning?  What antifreeze did you use?  How many hours on an the machine?
Let me know.
Eric