1988 Johnson 110 blows second drive shaft?????????

[StarcraftBrian]

This is the second time in three years the drive shaft snapped clean just under the water pump. Why is this happening? How can I fix it? Is the a particular year and hp lower unit I should look for that may be stronger? Thanks in advance, Brian

 

[Faztbullet]

Picture not working, is it even with top seal or higher???

 

[emdsapmgr]

Possible something was not machined correctly at the factory. For instance-the midsection top and bottom may not be machined parallel with each other. That could put undue forces on the driveshaft, just above the bearing in the lower unit. The late 70's V4 factory manuals make a big deal out of checking for parallelism on the midsection. Not much mention in later service manuals. Does the powerhead serial number match the midsection serial number?