I was given a Murry 4.5 bs mower and as soon as I put gas in, it started running out of the carb and primer bulb. I cleaned it really good with carb cleaner and replaced the float, pin and seat as well as the air filter gasket. It still will not put gas in the carb.

When I was putting the bowl back on the carb I noticed that there is an opening in the threads of the carb, does the bolt holes need to line up with this opening? I have tried several time to no avail, they are always off a 1/4 of a turn.

Should I have replaced the rubber O ring between the motor and the carb when I took the carb off to put on the new parts?

I originally thought this was fun to mess with but know I want to get it running like a scalded dog.

This is likely why you got the machine free. Sounds like you should consider a carb rebuild kit. The bulb may also be cracked and leaking fuel and not building pressure when you pump it. Your description of the threads being off is an indicationn that something is really out of alignmnet. During the carb rebuild you will see clear direction for your carb. If you aren't into rebuilding it may be time for a pro but it will run you about $100. You decide if the mower is worth it to you. New ones are about $200.