An Eye bolt is an important component of the motor. It is used in lifting the machine. The eye bolt consists of a loop at one end and a threaded end at the other. The threaded end is screwed into the motor body. 
When the motor or alternator is to be lifted, a sling is connected to the eye bolt and the machine is lifted using a crane. It is important to note the capacity of the eye bolt. Every Eye bolt has a WLL ( Working Load Limit). If this is exceeded the eye bolt will fail.
This can result in injury to crew members or even death. Check the capacity of the eye bolt before lifting.
The eye bolt is intended only for vertical lifting. Angular lifting (lifting in an angle) will cause the bolt to fail quickly. 
Angular eye bolts will have the safe Working load limit. As the angle of lifting increases, the WLL decreases. Thus, while the WLL will be maximum at vertical, it decreases as the angle increases. The angle of lift should be calculated and the safe Working Load Limit determined.
There are special types of eyebolts which can withstand angular load (up to a certain degree, usually 45 degrees. Check the angle with the manual).
These are known as shouldered eye bolts. Check that the machine has shouldered eye bolts before lifting the machine.