I have a Merc 260 with and alpha 1 gen 1 drive. The boat was running a bit warm 190-200 so I removed the lower unit and replaced the impeller and found a double gasket from the shop that rebuilt the drive last year. Had the heat exchanger cleaned and while I was installing the lower unit it was difficult to pull all the way up . I started and ran the boat on muffs and all was good but stiff to pull into gear. Not comfortable I pulled it back off. Found the stainless shift washer bound up, clearly my fault,,, But the shift leaver was in the right spot. After a closer look the extention that drops into the lower unit dis engauges the shift rod that sticks out for the main body. Very difficult to keep that tube aligned with the shift leaver when installing the lower unit. I cant find any info on this. Is something broken? Now that its all together I idle at 600 can shift into forward and reverse with no issue. When I come off plane and into the marina I idle at 900 I can shift to neutral and rev the engine and no change. I dont wonder if teh shift cable is out of adjustment?? can that cause the throttle to open slightly?