Reply To: Compression question

[billw]

The bottom cylinders on those engines tend to ingest water. You are lucky that thing isn’t seized up, like three quarters of the ones I have had. I would bet that the rings on the lower piston are at least partly stuck. Pretty much every 1950s 15 or any year 18 that I have ever taken apart has had rings stuck, to some extent, even if the engine seemed to turn over well before I took it apart. (The same is true for Mercury Mark 20s and 25s, by the way.) That being said, 130 is excellent and 110 is pretty darn good. Some people are fans of engine tuner, sea foam, etc. Maybe you should do the mag, carb and give it a good run with one of those mechanic-in-a-can things, and then retest. I doubt any harm would be done in trying.

Long live American manufacturing!