I recently overhauled a 1960 Johnson super seahorse 75 horsepower. I got it all back together and checked compression today. I only have about 75 lb.on all cylinders.The pistons and rings were replaced. The inside of the cylinders looked smooth. I don’t know if it makes a difference but it’s below freezing today and the engine didn’t turn over too fast due to the cold. Any ideas on what compression should be and if so what I would do to raise it up.