Small Engines (Lawn Mowers, etc.): Engine Runs Great, But Dies When or Transmission is Engaged Blades, safety switches, hp 40

Question
I have a 1999 Murray 12.5 HP 40 inch lawn tractor (Model# 40504X92A).  I recently moved and tried to fire it up at my new house.  I did some simple maintenance and it fired right up.  But when I try to engage the blade or release the clutch in a gear it dies automatically.  I can't figure out why?  All the bands are on track and clear (spin freely), but because the problems is dually associated with the blades and the transaxle it leads me to believe its electrically.  Since I've moved I'm having a hard time putting my hands on my old owners manual.  Another interesting thing is that when I got of the seat while it was running in neutral I expected it to kill, but it didn't...it just keep on running.  This whole thing has got to be somekind of bad switch problem, but I have no idea.  Can you help?  Jason  

Answer
These problems can be difficult to find but are often easly repaired.

Find all the safety switches on the mower; seat, clutch/transmission and deck.  Just follow wires to the switches.  Remove and re-connect each switch connector...I've seen corrosion on contacts causing this problem.

Also make sure the switch plunger moves freely and than the plunger actuating device is operating correctly;usually this is a tang/arm that pushes or releases the switch plunger.

Let me know what you find.
Eric