Have Boat Questions? Ask a Boat Repair Expert.
What year is the engine?
With the steering cable disconnected from the engine it moves freely?
Seems like you have done what we would do. It may be filled with corrosion and rust. a disassembly of the swivel bracket is the next move. This entails removing the lower unit and powerhead then disassemble the midsection. You'll need a service manual for the job.
When you squeeze grease in the grease fitting does it come out of the top or bottom or both?
Unfortunately there are bushings and rubber seals in the swivel bracket. So too much heat will damage them. Most grease guns will put more than 1000# ***** into the fitting. Try using a small tool to make sure the ball in the zerk isn't frozen. Push the grease gun on real hard a try again. You need to force grease in there and get the old grease out. If not then disassembly is the only other option.