Reply To: 1958 Johnson 10 hp

[need2fish]

Not for the faint of heart, but I believe you need to dismantle it to pull the crank and pistons out. The rings need inspecting — you can pull the exhaust baffle off and peer through the exhaust ports and pull the intake covers off. Both will give you some idea of ring and piston health, but not the whole story. Low compression may mean stuck rings.

Before you reassemble, find the torque specs and a torque wrench, and maybe a ring compressor. I’ve been messing with old iron for 50 years and I still break cap screws (like last night when I was dismantling a Johnson K-70 !).