No. Microlight engines are uncertified and all that is needed to work on them is a degree of competence. Owners are permitted to do their own maintenance, including completely stripping and rebuilding the engine. Log book entires are required for engine maintanance though, just like a GA type.
Spares are best procured from the OEM or agent as microlight engine spares. Some, like Rotax, use different parts and inspection standards on parts destined for microlight use rather than leisure vehicle use.
Some Rotax parts are common to the same engine model used in snomobiles, jetskis etc, but without detailed knowledge you are better off sticking to parts from the microlight engine dealers.