80 Chrysler 6 horse - reverse shift question

[twocyclemania]

I have a an 80 Chrysler 6 horse that's almost new. It's up and running and I replaced the impeller. After the replacement I found I had a hard time shifting into reverse and had to hold the lever in reverse all the way to get it to go into gear and had to hold it there to stay in reverse. When I dropped the lower unit for the impeller job there was only one bolt/screw that held the shift lever on and I did not make any adjustments. I think it lines up with only one hole to the linkage. So it looks like you can't make a mistake. Before I did the impeller job I had it running and it was shifting smoothly. Any ideas on the adjustment or where I messed up? thanks