The thing is that this Renault 4 engine that I have was mounted in my boat (a Weedo GT with an inboard engine based on R4 1108 cc, when used as marine engines they are called Mercruiser 60). Instead of 33 hp, this engine has 60 hp with double carburators.
The compression seems to be really low, I haven't yet had the possibility to measure the compression, but when I rotate the flywheel there is almost no resistance. Of course I need to open the cylinder head to see if the cylinders isn't worn out/damaged, but I need to see if I can ever find spare parts before and then get onto it.
I bought the boat and engine disassembled from each other, so I don't really know the status of the engine, just suspecting something bad.