I have a 1989 Merc Black Max and I can start it a number of times with no issues. But every so often it will start like I have something in a cylinder and at like it has Hydraulic . I turns over up to a cylinder and stops. It even backfired once the last time I ran it last year. It runs strong when started. I have the separate oil removed so its premix now. the cylinders are 120 compression across all of them. I don't want destroy it so looking for advice to what may be going on. Right now I haven't run it this year but just opening it up. Thinking to have it looked at and see what is going on also. So anyone please leave a comment on what you think I need to look at?
