They were a good very reliable engine , I bought one new in 1977 also had the exact same engine that ran on kerosine too for a fishing boat I had .
bit on the heavy side though ,I used it on a Zodiac 10 ft 6 inch sib on a regular basis during the summer months until about 1990 and only sold it about 4 years ago ,
in all that time it never broke down and always started on the 3 rd pull,
Down side was that the prop has a sheer pin instead of the the modern style hub and after a while the pin hole started to get worn and became elongated no problem as the prop slot had worn too I just reamed out the hole and went up a size sheer pin .
It also only ever had one new set of ignition points changed in that time.
A good reliable engine if a bit of a heavy lump but I'm not too sure if I would part with a load of money for an engine getting on for 35/ 40 years old.
I still use an stripped out powerhead /engineless model for one of my old y boats when used as a display boat for Rnli events especially if we are doing a long distance boat pull .