Re: Fuel shooting out of top right corner of carb when priming fuel bulb...new float?
The seat is what the needle goes into. You didn't give the year and horsepower of your motor but there is a good chance that your needle seat isn't replaceable and is permanently pressed into the carb. If that is the case, clean the seat as best as possible. You may also have to do something like spin a q-tip with valve lapping compound to recondition the seat. Whatever you do, don't scrape the seat with anything like a pick or sand it.
You may notice that your new float needles are completely metal instead of rubber tipped. The stainless steel needles are designed for harsher fuels (ethanol mixes) in mind.
Don't forget to order a carb gasket set. If your float needles are shot, there is a good chance that your gaskets will be old enough that they will need replacement as well.
Warning: Personal rant about automatically blaming ethanol 100%-----> I am by no means a fan of ethanol. I personally hate it all the way from the politics of corn subsidies to how it makes engines run. However, engines that are used seasonally (lawn mower engines, boat motors, motorcycles, snowmobiles, snow blowers, string trimmers, etc) have always had problems with carbs needing to be rebuilt. Travel to non-ethanol states and every spring you will still see people cursing while trying to start their lawn mowers and boat motors. It is due to gas going bad and gumming up the carbs during the off-season and/or gaskets and rubber parts finally giving way to age from not being used. Ethanol does add fuel to the fire by making gas turn bad faster, in addition to it being harder on gaskets and rubber parts. This is why it has always been recommended to either run your motors dry at the end of the season or manually drain the carb bowls.
TLDR Version: Bad gas has always been an issue in seasonal engines but people are now blaming ethanol completely for carb issues. Ethanol cannot be blamed 100% for bad engine storage techniques and/or gaskets and rubber parts not lasting indefinitely.
Finally, even after my rant about blaming ethanol, I still recommend running ethanol-free gas if possible.