GX22 Dies On Full Throttle

I picked up a Mantis 7260 Tiller with the Honda GX22.  It has needed quite a bit of work to this point and I want to put more into it but if I can't get past this, I will have to abort this project.
 
I have done a general tune up and clean up.  New CR5HSB spark plug, new air filter, new fuel lines, new filter and new ebay carburetor.
 
Right now, it starts up and runs but if I try to run it full throttle, it dies.  It will stay running and increase engine speed all the way until it gets around full throttle.  It also doesn't seem to have alot of power but it could also be a slipping clutch or that the tine transmission needs some rework too because the tines don't spin very fast and there is some noise.
 
I found the maintenance instructions for the WYL series carburetor so I can tune the mixture and I tweaked the metering level a little bit to get set it like it says in the manual.
 
I picked up a cheapy compression gauge on ebay to check the many small engines that I like to work on and I gave it a shot last night.  It only measured around 24 psi but I also measured the compression of my Homelite BX90 leaf blower engine and it also read around 24 psi.  So I'm not sure yet if they both have low compression or I have a bad compression gauge.  I wouldn't think the GX22 would run if it had half the compression it is supposed to have but I don't know that much about the necessary compression.
 
Does anyone have any ideas?
Thanks!

I tried it without the driveshaft and it still dies under full throttle.  So all the drag in the transmission isn't a factor.
 
Without the drive shaft I also realized that I have a lot of dragging metal noise in the clutch so I will also be replacing that if I can get to the bottom of the dying at full throttle.

I'm pretty sure it is the right carb.  I bought it from eBay but it looks exactly the same as the original and the listing calls out the GX22 as a motor.  The part number isn't the exact part number as listed on Jack's for my Mantis 7260 tiller.  I can't view the exact listing anymore but the eBay listing title says it is a 16100-ZM5-803.
 
Unfortunately there are no adjustment screws to tweak the high and low rpm.  The only way to adjust it is to tweak the metering lever.  I found a forum post about adjusting the WYL series carbs, referring to the service manual that details the adjustment.  So I bought one of those Walbro gauges and adjusted it to how it described.  It says to adjust the metering valve so "The gauge should pass over the lever while making slight contact as you pass it over".  Maybe I need to just adjust it to make it run richer than it describes?
 
The only 16100-ZM3-848 Honda brand WYL 132 carb that I can find is $75 on eBay and it is way more that I'm willing to stick into this thing.  Maybe I could buy the OEM parts here on Jacks and rebuild the one that I pulled off but I can't help think that this one just needs some tweaking or something.

Yup, according to the WYL series service manual, there are two types of idle mix adjusters and mine has one with a rubber cap and an "inner" adjustment screw.
 
I played with that setting and now my engine runs wide open throttle!!!
 
On to replacing the output bearing and rebuilding the transmission...