Won't run unless choked!

I own a Porter Cable PWH2500 Pressure washer. It has a Honda GCV160 5.5 engine on it. Not sure the carb make yet.

The unit is not used much (probably 5-10 days a year) but has always had gas stabilizer in it and I drain the tank when I am done using it.

The unit starts fine when fully choked. After letting it warm up for a minute or two, I attempt to take the choke off.

The unit will run about 1/3 - 1/2 choked, but dies it I try to remove it completely. So, the unit runs, but at much less capacity (power) that it should.

I am assuming this is a carburetor problem where it's not getting enough fuel once the choke is removed and is running so lean, it stalls almost immediately.

So, several questions:

1. Does this diagnosis seems correct?
2. If so, does it need a carb rebuild or a new carb?
3. If not, what else should I be checking?

Thanks!

Won't run unless choked!