Re: lost boat motor
I know it's hard to walk away (swim?) from lost equipment, but consider the value of your time, times the several hours you have now spent, to pull up a $75 motor? That may or may not run again but guaranteed will need more hours and at least a couple hundred dollars to fix?
3 weeks is a long time for fine grain silt to get in everything. Initially there is the rust issue but now you have another issue that may require more work.
But I wish you the best and you can be right proud if you retrieve it and get it running!