If you are planning on installing new rings, you’ll have to break the case open and pull the pistons anyway. If it were my motor, I’d pull it apart and check the bores for being round or out-of-round. If bores are within spec, then hone them, install new rings and crankshaft seals, then re-assemble. But even before that, as Tubs suggested, I’d run the motor for awhile and see if it’s just stuck rings causing the low compression. Running for awhile with modern oil and maybe some OMC Engine Tuner might clean up the rings and improve compression.
Bob
1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1957 Evinrude 3022
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20
1982 Evinrude 25hp
“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."
