Interesting photos! Before I learnt about small engines I used to get the mower serviced. It would sometime come back with loose cowlings or screws missing. I never complained because usually the mower had stopped working and I was happy to get it back so that I could continue to cut the lawn. I now realise that the place I took it to probably spent a few minutes blowing out the gunk from the carby and just slapped it back together. The bloke called it a service and I guess it was sort of.