On Aug 22, 2020, at 5:44 AM, Arno Luijten <arno.luijten@...> wrote:

I agree you should avoid common rail diesels if possible however 50 Horses engines are still mostly classic injection. Volvo D2-55 could be an option. This is a re-badged Perkins that gives you a little extra power. Volvo can give nice rebates on re-powering if you push them a bit (I have experience).  These 4 cylinders run very nicely. Also have a look at Beta and Nanni. Nanni being French may have have specific experience with Amel. Keep an eye on the weight of the engine the older designs tend to be quite heavy.
Also look carefully at the design of the engine from maintenance point of view. Some engines have impellers and oil filters in places very hard to reach for some boats. For example; my engine is a D110i-C. This model was designed by someone clueless about converting engines for marine use. VP must have fired him as the later models D-H models) were very much different.
So for your Sharki look beyond the initial purchase price. Part prices, availability of parts and effort to maintain are also things to consider.