I have a 4hp Mariner 6E0-00 30080, not sure of the year, maybe late 80's. The shift lever will not move. (its stuck in neutral). I removed the lower unit and it manually shifts fine, no problem, nothing binding. With the lower unit off going back up to shift the shift handle it will not budge. Visually I do not see any problem in the lower cowl where it would normally click over and shift, but the shift mechanism sure is binded up. any ideas? thanks for any info.