I have a 25 hp kohler craftsman mower. Set for a few weeks, now it turns over ,will fire up when gas is sprayed into carb but dies. I am getting gas to the carb.

Hi,
Either carb is gummed or solenoid is not opening. Solenoid should click as it opens, or can be felt by holding and turning on.
It is classic symptom to have it start when induced but not continue to run. Means a dirty or otherwise nonfunctioning carb.
Peace,
Clarke

The fuel solenoid was sticking

Hi,
Lots of times it can be removed, sprayed with aerosol carb cleaner, have the plunger worked in and out and repeatedly sprayed again to free it up. You do not want to replace it if you can avoid it, generally $60 - 75.
Peace,
Clarke
PS if you give engine numbers I can look it up; I could give a link to the engine's service manual if you like.