I second the recommendation for a new glow plug, I use OS #8. It would also be good to get some new fuel. Once you get it running, you can go back to trying the old fuel. Attach a piece of fuel line to the carb and blow through it to confirm the spray bar is not plugged. While blowing, close the needle to confirm it seats. Do the same at idle to confirm the idle needle is open enough.

If the engine was working when it was put away, you should not need to disassemble it. More problems are caused by improper reassembly if you've never torn down and rebuilt an engine.

Fuel usually does not move through the line when you're flipping it to start. In fact, on some setups, after the prime the fuel goes back into the tank, but as soon as the engine fires, the line is full again. Make sure you get a good prime.

When priming the engine, open the throttle all the way, and do not connect the glow driver. After priming, close the throttle more than the 1/2 to 3/4 you mentioned. I have a few engines that just won't start with the carb opened that much. I usually start my engines with the throttle at idle, or perhaps fast idle, setting.

Do you have the muffler on, and are you running muffler pressure?