Bulb/fuel line issue….

[steplift20]

I know it's a pain in the ash. But that would tell you more if you use a portable tank. It's going to tell you that your issue is somewhere in the fuel delivery what I would do in this order is Ask Spareparts lol.
If it runs good on a portable tank the next step that I would do is replace the primer bulb with a Mercury bulb. True it's more money but it's worth it.
Next I've you still have a issue I would take the pickup tube out and check it for blockage, buy wait a secound it just came to me, do you have a water sepperator? If yes. Change that first cause that would cause you to lose power ,, but next change the inline fuel filter too. I would do that definitely first if you have a water/ fuel filter, it looks like a cars oil filter. Good luck. I will be watching for a post.