1990 80Q dies when wet?

[Dave C]

This is a typical symptom of bad ignition wires.  Are yours original?  If
so, do yourself a big favor and replace them.  One way to check them is
with the engine running in the dark ... look at the wires to check for
sparks/arcing.  Try spraying water over them while doing this test.  If the
wires are original, and even if you don't see sparks, replace them anyway
cause they are likely causing other problems.
Dave C