Sometimes, people will say anything to get a car sold. So the seller's story is open to question. I have gotten deals in the past by telling the seller that it doesn't run, so I have to assume the motor is bad and my offer is based on that. That went well when a friend was interested in a 52 MG TD. I looked at the car and looked under the hood. Advised my friend to buy it at the proposed price for car with bad motor. He bought it. We pushed the car a couple of blocks down the street, so the guy who had just sold it couldn't see us. I opened the hood and put the plug wires in the right order. It fired up and he drove it home. I hate having to spend the time getting a car running that I might possibly be interested in. But, if you are interested enough in the car to spend some time on it and you think the guy is honest, you might try jump starting it off your battery. You might also check voltage drop along the cables. It could be the starter relay. Although it clicks, the contacts might be worn badly. It could be water in the bulkhead connector. It could be coincidence and have nothing to do with the spray. Could be bad cable, bad starter, bad switch. You could wind up spending some time on a car that isn't even yours.