Old boat engine - is it still good?

At the latest when it comes to buying a used boat with an equally used engine, the question arises as to how the most expensive single piece of equipment on the boat, namely the engine, is doing. Especially during the first inspection, the effort has to be kept within limits, and so the things that even a layman can do without special tools are presented here. For this purpose, procedures are then presented that are used in more difficult cases and are applied by the expert.