As the instructions say, I remove the tubing from the check valve and then fill the tank with fuel as directed. I'm running a MP5 pipe with the pressure fitting on the pipe clamped off with fuel tubing.

My question is, after filling the tank are you supposed to connect that line back to the check valve or does it remain unplugged? The only way I can successfully start the engine is with that line to the check valve remaining disconnected. As soon as I get the engine started and I place that line back on the check valve, the engine dies withing a few secs.

What am I doing wrong? I'm running the engine with the needle valve and idle needle set per the instructions; main needle valve opened 1.5 turns and idle need open 1 turn. It seems to run too rich with alot of fuel dripping out of the pipe when the engine is running.

Yes you need to reconnect the check valve so that it can pressurise the tank (that's the whole idea of the system). You should be doing this "before" you attempt to start the engine.
Just turn the idle needle in 3 clicks at a time until the engine will idle. The factory will have everything set to rich in the instructions, so that the engine can't be damaged during the 1st runs.
After every run, you will have to disconnect the line from the valve to tank straight away, or the high pressure in the tank will keep forcing fuel into the engine and flood it.