1983 Johnson super low compression

[Robert48]

Hi I have a 1983 Johnson 15hp that only has 10 PSI in both cylinders yet still runs. I did not think this was possible. PSI tested with multiple testers. No outward signs of head gasket failure. Does not smoke excessively. It can be hard to start but then seems to run pretty good. Any ideas what is happening? thanks!

 

[lckstckn2smknbrls]

My guess is the rings are stuck. Might be time to decarb the motor.