[TimBSmith]

Great to see your post. I am in the early stages of my own A4 adventure on a 74 Pearson 30.

You are already hand with engines which I was not. I have come to enjoy this community, learning about, and gaining confidence in my ability to service and safety operate this great old gasoline engine.

My boat had sat for nearly 3 years. Once well cared for the owners of the past 3 years just didn't seem to have time for much work on the boat.

The recurring patterns I have read here and experience on engines sitting.

Compression. Many many seized A4 motors are salvageable. If you cannot run a compression test (and that is the first evaluation I learned to do) What is your path too accomplishing this? I have read about but not needed to pressure test the block on a seized motor to see if you have something to work with. Then doing the work to unseize and rebuild as needed. All of this covered extensively in this group. Nothing seems to fire our MVPs up like a) unseizing a motor, b) a rebuild story, c) exploring prospective diesel repowering decisions where primary influencers are diesel owners and mechanics that want to work on diesel engines. (Confirmation bias).

Fuel. The MVPs here often run the engine dry before powering down at moorings and remove their carburetors in the off season. A carburetor cleanup is probably in your future. That is where my fuel system evaluation, end-to-end eventually led. And next to verified compression, fuel and carb care seem to be vital to safe and dependable operation. Discussions about ethanol gasoline and oil preferences run deep here.

Spark. My favorite post this year(next to rebuild stories) was from a member that developed a waste spark computer ignition system (maybe Rasberry Pi based?). I had learned about the traditional point, electronic, and then the waste spark innovation really brought this all together. I have an electronic ignition. I learned how to test the system end-to-end to confirm ignition circuitry and spark quality. Best $30 I spent is a tie between a remote starter and a pair of knee pads. I still need to lookback and remind myself why my coil/ignition system has a resistor from-time-to-time. The history of coil overheating and burnup is no joke. Again and again you will see reminders to turn your ignition key off if you are not spinning the motor.

Exhaust. Especially the riser. I recall so many stories where dormant engine broken risers have been discovered in dormant boat scenarios. Once my motor started(on the hard) I discovered both riser and wet exhaust hose needed replacing. If I had a dormant A4 boat scenario I would probably give the riser some test taps with a hammer and even unwrap the riser and take a really careful look.

This is a small fraction of information that may or may not be relevant to you. I am just finishing my redshirt year here and still very much a freshman. All the best with your A4 and sailing your new-to-you boat.