Same as our Red Max BT250.
First 90 psi is not good compression on these should be more like 120+. Really surprise it even runs as most 2 cycle around here needs at 100 psi to even hit.
Also check for a clogged spark arrestor. When they are clogged they will cause flooding and lack acceleration at the same time as fuel mix can not burnt without oxygen.
No fuel on return might be a little normal as not all primer prime the same they primary meant to remove the air from the metering chamber. Now if it pushes some fuel out and then sucks it right back in then you have bad primer check valve. There is also a few other problems can happen during priming if there is a leaking main nozzle check valve or a welch plug that is leaky.
But with only 90 psi I would more worry about the PNC (cylinder(sometimes called the Jug) and piston condition).
