The engine was made on 29 March, 1984, so it should have electronic ignition.

Here is the Illustrated Parts List:
http://bsintek.basco.com/BriggsDocumentDisplay/Z6nlyHVJ1DajI.pdf

Here is the Operator's Manual:
http://bsintek.basco.com/BriggsDocumentDisplay/msoBGL-K_ny7tH217FzoPu.pdf

The carburetor is a Large One-Piece Flo-Jet, which is probably the most reliable and durable of them all, as well as the easiest to clean.

I suggest you begin by removing the carburetor, and looking in the engine's intake port to see if it has water in it. Then remove the spark plug and see if you can rock the engine by moving the flywheel slightly in both directions. Next, drain the oil and see if there is water in it. Tell us what you find, and we can move forward from there.