Small Engines (Lawn Mowers, etc.): Kohler engine looses power under load after warming up, fuel pressure gage, plastic connector

Question
I have a Snapper 1600A lawn tractor with a 16 hp kohler model k341AQS (spec 71243a) engine.  In spite of repairs I have made to the tractor, the problem I am about to explain has progressively gotten worse.  After about 1/2 hour to 45 minutes of using tractor under load (to mow), tractor starts coughing until it stalls.  It will continue to run if I shut the blades off (prior to it stalling).  I have replaced the points, condenser,coil, fuel filter, and spark plug.  The coughing to stall problem will now show up after only about 10 minutes of mowing.  I was told to check the spark plug to coil wire by spraying water on it while tractor is running (if wire is bad tractor should lose power - it did not).  I also jumped wire (once tractor started coughing) from coil to battery - it actually seemed to cough more.  I have inspected wiring diagram (in manual) against wiring on mower - everything appears to be in good shape.  I attached a fuel pressure gage to check pressure while using tractor.  As tractor started to cough, pressure went up.  I heard if it was a fuel pump problem, the pressure should have gone down.  Also, it seems fuel pump problem would exist regardless of operating temperature.  The only change I have made is: the plastic connector which holds wire harness to ignition switch has deteriorated (replacement unavailable), so I had to directly wire wires to ignition switch.  There was some shorting and I'm sure heat build-up prior to my discovery that wire harness connector/insulator was deteriorated.  Could the ignition switch be bad? But would it only act up after engine warms up? I have been told to create a new wiring harness with individual wires (considering they seem to be unavailable to buy), but as I said the wires and harness appear to look good.  This tractor is in very good condition (especially for the year).  The first time I noticed this condition was after using a pull behind weed sprayer which is hooked up to the battery.  Might or might not have a connection, but I can't get the fact that it ran perfectly before using sprayer.  I have used the sprayer several times prior to this year without any trouble.  Sorry about the length of this explanation, but I didn't want to leave anything out.  

Matt  

Answer
 Hello Matt:

 The Only Thing I can see that Wasnt Done to Cure this Problem was Clean and Rebuild the Carburator. Because of the Cool Gas FLowing through the Carburator, it Takes Longer to Heat up and Starve the Engine. A Carburator Doesnt Reach True Operating Temperatures until Approximately 25 to 45 Minutes. The Time Varies because of the Outside Temperatures and Gas Temperatures, Ect. I have seen this Happen a Lot. Being in the Yard Maintenance Business, it Happens more Often than with Home Owners. The Varnish that Gas Forms Inside the Carburator Restricts the Flow of Gas to the Engine and in Turn the Fuel Pressure goes up. Hope this Helps. Let me know what Happens, Please. I enjoy knowing the Outcome. Thanks.

 Good Luck

 Respectfully

 John