Kohler KT735 Motor Issues

Greetings  ..... I have a Gravely  Zero turn with a KT735 Kohler   engine that has some starting issues ....seems to start fine when cold in the morning but after it runs for a while will run rough and if you shut it off  will not start ....I have trouble shot some of the issue and have found that the choke is not closing all the way when trying to restart engine ...It has the smart choke which is a heated spring that controls the choke ... I have checked the specs on the spring resistance and it is within specs .... If you try to start the engine cold or hot and it doesn't run and with the filter off you can see choke is not closed all the way ....maybe 90% and if you push it closed with your finger it fires right away and runs fine  .....any thoughts? 
 
cpl of side notes .....mower is not actually mine is my neighbors and I am going by his description of the issues.... when I first started looking at the problem started the mower and it seemed to start ok cold and then ran it around for a few minutes and then shut it off and then when I attempted  restart and had the no run issue ....pulled the filter and closed choke by hand and it fires right up .....    thanks in advance   ....   mike bell ... NE Fla ......