Engine shut off

[Revzun]

I'm needing some info. I own a 1987 MCI 102A3 and starting it is not a problem and I have ran the engine on hi idle for 10 to 15 minutes but when I switch on the A/C system the engine will continue to run for 2 to 3 minutes and at that point the auto shut off
Solenoid Activates and shuts off the engine. I can restart it as soon as I release air so that the shut off solenoid is released.
Thank you in advance for any help