When an execution is delivered to an officer he shall proceed without delay to levy the same upon the property of the defendant found within his county not exempt from execution, unless otherwise directed by the plaintiff, his agent or attorney. The officer shall first call upon the defendant, if he can be found, or, if absent, upon his agent within the county, if known, to point out property to be levied upon, and the levy shall first be made upon the property designated by the defendant, or his agent. If in the opinion of the officer the property so designated will not sell for enough to satisfy the execution and costs of sale, he shall require an additional designation by the defendant. If no property be thus designated by the defendant, the officer shall levy the execution upon any property of the defendant subject to execution.