Small Engines (Lawn Mowers, etc.): Shindaiwa blower- no power, dies., crankshaft seal, compression issue

Question
I have a shindaiwa EB501 blower.  It took some TLC to get it started, because the spark plug kept getting wet. It was also leaking oil from somewhere near where the plug screws in, have not found a hole or bad gasket yet.  It has no muffler screen on it to clean.

I initially suspected it a clogged carb issue, as it won't go full throttle ( sounds like "Blahhh"). It has the non-adjustable style carb, (as opposed to the H/L screws like my Echos, which are simple to clean/ adjust)  I have cleaned the main jet, and every other oravice of it, same behavior.  

I did notice when I cover the pipe halfway, it revs up alright; once I take my hand away, it slows and dies on any throttle setting/ half choke or whatever.  

Does this sound like a compression issue or what?  

Thanks Much!!

Answer
Could still be a carburetor problem, but I wonder if you have checked the muffler or exhaust port. The other thing is a air leak. I really have never worked on a shindaiwa, so if it is an air leak, I don't know which direction to send you, but with an echo it's almost always a crankshaft seal.