Small Engines (Lawn Mowers, etc.): STX 38 stalls after 30 min of running perfectly, walboro carb, kohler command

Question
Hello PK,
My 1990 STX 38 starts perfectly and runs excellent for about 30 min, then stalls like it's out of fuel.  Will not restart hot.  Once cool, will restart and run fine for about another 30 min.  I suspect the fuel solenoid under the Walboro carb.  It does feel quite hot after 30 min of running (hotter than the motor I think).  Fuel is fine, plug and oil are new, air filter is new, fuel flow from tank through filter to carb seems fine, vent in gas cap is clear.  Opinions?  If solenoid is deactivating when hot, how difficult is it to replace?  I have a great deal of automotive mechanic experience but have never taken one of these apart before.  Should I get a rebuild kit?  Does the solenoid come in the kit?  How do I get the right solenoid if not included in the kit?  Where is the best place to get these parts?  Any pointers on what to watch out for when rebuilding; ie. springs or check balls that pop or fall out when disassembling.  Can someone guide me through this a little bit?  I suspect that a new solenoid and a good cleaning with carb cleaner may do the trick.  What do you all think?  Thank you very much in advance for your assistance!  Best Regards,  Bob Lituri
PS. I can't see the numbers on the carb -still on engine.  Can get numbers if needed.  The engine is a Kohler Command CV 12.5S, Spec No. 1215, Serial No. 2009401168.
BTW, could a funky ignition coil cause similar symptoms?
Thank you again for your help!

Answer
I don't have that spec number in my look-up.  John Deere often has manufacturers give their parts special numbers that won't cross-reference so you may have to call a Deere dealer to get the part numbers.

The solenoid just unscrews.  There are a couple different types, one holds the bowl on the carb body, and another has an internal nut assembly.  You may find it difficult to get a wrench in the small gap.  I take the cheap wrenches you find for a dollar or two and grind down the face of them so they fit.

Usually the coil is the prime suspect, especially when the failure is so reliable.  When the engine dies, immediately test the spark.  An inline spark tester is best for this.