I have a 1999 27 Fountain Fever and I was curious if anybody knows the size of the actuator I need. The boat is shrinkwraped right now so I can’t go and find out.

Can't tell you what you need but there are numbers on the unit and once you have them it is easy to replace. Did mine a couple years ago, found a supplier just a few miles away that took good care of me, ordered and here in a few days. I thought it was going to be a real nightmare to find the replacement.

Local, nearby town, industrial supply shop. They were listed as a dealer by the manufacturer of the actuator in my boat. I believe I still have all the info in my office. Will look first of the week.

Do you know the manufacturer of yours?

I believe Warner Electric was purchased by Thompson Actuators. The case and length are usually industry agreed standard so many aftermarket options.
Only a few offer the marine certification. The original Warner's did not have the certification, well my older one I replaced did not. I found by far the best deals on ebay. Good Luck