Quote Originally Posted by BigRiverMarine View Post
On a Johnson/Evinrude you have a fuel/choke Solenoid. It's the thing on the right side of the engine with the red lever on it. If that is bad, and they go bad often on older engines like yours, it will cause the issues you've described. You can rebuild them if they aren't to bad. The diaphragm and the O rings around the red lever go bad in them. If the electrical is bad in it, you need a new one.

BTW, you can remove the top on the solenoid (the part with the red lever) to replace the bad parts. Look for cracks, and leaking fuel which causes them to suck air. You can buy the entire top part and the diaphragm if the electrical isn't bad. The red lever allows you to put the solenoid in manual choke opposed to electrical choke.

Without seeing and running it, this is just an idea of what's wrong. With the carb freshly rebuilt, and a clean filter, I'd bet ya tho, unless the fuel line has deteriorated inside and has blocked the jets in the carb After the rebuild, but that wouldn't cause it to over rev in neutral like you described.
Could that be the staring problem to? Thanks for the information!!