Chendo from California

Have David Borwn model 880 selectamatic with 3 cylinder diesel engine worked great for quite awhile, then my problem started. while working tractor doing road grading with gannon, engine stops like someone pushed shut of valve. checked fuel OK, checked all fuel lines for tightness OK, checked fuel lines for debris OK, bled fuel system, started engine OK, put to work within 20 minutes it stops again.repeated procedure mentioned above ,same thing happened, I am at a loss, can someone help me ?????????? Chendo......:thanku: