Hi Tony,

There are two possible things happening here:

1. there's a problem (low oil pressure most likely in this case) - as soon as you release the key, the alarm kicks in and stops the engine (the key overrides all safety switches).

2. There's an electrical problem - loose connection, bad contact, etc. It could be in anywhere, really.

Does the control panel indicate any alarms, or anything like that?

Hope this helps - please share more info if you find out anything.

Thanks, Cas