If memory serves me, the High is closest to the engine. Low is on the left towards air filter.
My pb-500 is out on loan to a friend, otherwise I'd could just go take a quick look.
After I changed the metering block of the carb, it quit fighting me and I sort of drifted off to other things.
https://www.arboristsite.com/commun...s-at-full-throttle.263144/page-2#post-5039226
Prior to that I had made sure the reeds (all three locations) were pretty flat and had no bad gaps at rest.
The intake reed had one petal that sat a bit open, so I flipped it over.
hmm, doing This actually put the burr side -away- from the reed block too.
As you would expect, that made cranking the blower noticeably easier.
Do NOT forget to use a thread adhesive IF you so much as touch the reed screws!
Clean and de-oil the screws (and the holes) before applying the it, or it won't hold.
Failure to do this properly, will very likely result in a destroyed engine when a screw comes loose.
A touch heaver than 50 to 1 for the fuel oil mix helps keep the reeds "wet" and sealing better.
I've used 3.5 ounces to a gallon (Echo Red Armor oil) and for the last few years am pretty content with how things .....start, tune and run.