I am looking to replace my lower unit on Johnson V4 88hp 1990 year. What year range of units and HP will fit? Also will different HP and different year make a difference in performance or durability.
Most any 1978 to late 90's V4 LU will bolt up and work if the correct shift rod height is used. Some big V4s used a V6 style LU, those wouldn't work. No performance or durability differences between year models that I'm aware of. They are basically the same. What's the issue with yours? I've got some spare parts lying around...
Any V4 gearcase from 79 on will bolt right up. If you get one from a looper you'll need your shift shaft. No big deal. Any V6 or V6 style from 79 & newer will bolt up and work but they use a different gear ratio and a bigger prop. A V8 gearcase will bolt up but I can't believe anyone would do that. We'll assume your motor is a 20" so just make sure the new lower unit is a 20" too.
Personally I'd stick with the V4 case. Less drag and you can use the prop ya got.
