lower unit question

[koma80]

My son is swapping out his lower unit on his 74 model 85 horse merc with a 81 model 80 horse merc my question is 85 has a thrust button on the driveshaft and 80 doesn`t is there going to be an issue with out it?I`m getting old and have the sometimers at times

 

[Chris1956]

Not sure what a "thrust button" is. I would expect the gearcases will exchange /o issue.

 

[wired247]

He's talkling about the spring loaded pin at the top of the driveshaft on the early models. As long as the driveshaft came with that lower he'll be fine.