Ryobi leaf blower won't start

I have an old Ryobi leaf blower (Model # RY08554) that seemed to be losing power (i.e. not revving up as much as it used to) so I tried adjusting the carburetor. Unfortunately, that just made it worse, to the point when I got it started, it would only run for about 5 minutes before dying. I tried resetting the flow screws (1 & 3/4 turns from close on both the high and low needles) no help. After further adjustments, taking it apart and cleaning it, I gave up and purchased a new carburetor that came with a spark plug, fuel lines and fuel filter, which I used all of. Unfortunately that didn't make any difference at all. Even though I had fairly fresh gas, I went out and got some new gas, but again, it didn't help. I tried loosening the gas cap, didn't help. The only way I can get run for a second or two (proving that it is getting spark), is to spray some "engine starting fuel" down the carburetor. At this point I don't know what else to try.

I would appreciate any ideas on what to try next.

Thanks!