Help!!! My engine won't crank at all

I tried to start my 317 after it has been sitting over the winter(in a heated garage). I had cleaned the carb and was cranking it over to try and get the carb filled with gas . It tried to start a couple of times , then the battery wore down. I charged the battery and tried to start it again but this time I only got a click. I assumed from the solenoid. I bought a new solenoid, but that didn't solve the problem. I checked the ignition switch and found that the double red wire had gotten hot( I guess from cranking so much) and had melted through the plastic connector cover and the ign switch looked corroded so I thought that might be the problem, but it wasn't.
I jumped the starter directly from the same battery and the starter turned, so I know the starter is ok. I am at a loss for what to check next. Could it be the battery? I had it checked at oreileys (they said it was bad) but auto zone checked it and said it still had a little life in it. Any suggestions or experience with this problem would be greatly appreciated!
FYI , it's a 1983 317 with an Onan 18 hp engine.
Thanks
Mike

Pen, go buy a $4 bat hydrometer (turkey baster-like). Check the electrolyte in each cell. A voltage check sometimes means nothing as coatings on plates can take a charge and give a false voltage reading, while the electrolyte will tell the true story. Rule of thumb I use. Don't crank the engine over more than 10 times whithout a cool down. Stop and make some other checks. :2cents: