We can ship new engines without any restrictions, such as chain saw, motorboad-motor, bike-motor etc.
As soon as it is an used engine running with liquids (such as oil, petrol), we can ship it emptied only - and need a certificate that it was emptied by any entitled garage. Only then it can be flight as Non-Dangerous-Good. Otherwise it will be treated as Dangerous Good, which requires a lot of effort and is costly. Such certificates can not be issued by myGermany.