85 Trans Am 305 carb. Been running fine. After two days of heavy rain it won't start. It fired up the first time, after that it won't. Voltage is good until I turn key to start. Then volt meter in dash reads nothing, dome lights go out, etc. If I turn the key off, then back to on position everything is lit up again. Starter is dry and clean, couldn't see moisture in distributor cap.

Update: So I used a jumper cable to run 12v to the starter. It did jack squat. So I pulled the starter. Hooked the jumper to it again with the starter pulled and it kicked out and spun fine. Put it all back together and the bloody thing starts and runs again. Would still like to hear some ideas in case this happens again.

 

Bad/going bad starter solenoid ? Loose and or dirty connections ?

 

I'd say check under the distributer cap again. Pull out the ignition module and see if there's moisture under it.

I had a 1980 Firebird that did the exact same thing. Got some heavy rain, it fired up once but then it would only crank and never get any spark. I pulled up the ignition module and it had moisture under it that corroded the connections on it.