The most common issues are the steering cables
seizing up...most Gemini
owners need to replace them every several years...but the problem would happen whether the rudders are up or down. It should be easy to see if something is impeding the movement if you have someone who can turn the wheel
while you look under the swim step (if it's a 105M or Mc). There are lines to the saildrive
that might be caught on something, too.
owners list-serve on Yahoo has diagrams and videos on how to check or fix just about any problem. https://groups.yahoo.com/neo/groups/Gemini_Cats/info