Denise030 and Chicory83, thank you very much for your input!
Ok, so I didn't know that the compressors get that warm. Honestly, I never checked the temp before I started having issues.
By frosting up, I mean that after about a half our there is a thin film of frost forming all over the evaporator. There is no frost on the line returning to the condensor and none of the connectors had any oil or oily residue.
Here's a photo showing some of the connectors and components:
I don't know how old the unit is. I've had the boat about a year but I would guess the system is less than 10 years old. Being a BD-50, I believe it has R-134A. It does have an attached LED for diagnostics, but it doesn't blink (at all). There is no other condenser fan that I am aware of. Just the keel cooler, compressor, evaporator and associated wires and coolant lines.
BTW, I did not think that warming it and restarting it would "fix" anything. However, from other forums it appears this can sometimes squeeze a little more life out of the unit as the contaminating water vapor (if that is the issue) may melt and move to an area where it might not freeze up and cause a blockage. Thought it couldn't hurt..
Honestly, I don't plan to roll up my sleeves and give it the old diy effort. I like to do some research before calling in the professionals for the following reasons:
1) Less chance of getting bamboozled by a less than knowledgeable or honest technician.
2) With a little background understanding, I might actually understand what the tech is saying to me.
3) Might be able to figure out ahead of time a rough guess of what this might cost me
With this additional information, is anyone able to figure out a likely culprit?
As always thank you all for your help!