Stihl br420c backpack blower wont start

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Where did you buy the cylinder and piston? You may want to exchange it for another, or return it and watch for a good oem P&C on eBay.

Unless the carb is so out of whack that it won’t run it sounds like it’s just low on compression. 80lbs is too low.

My 420 is all original, I’ll throw a compression tester on it today and see what readings I get.
I purchased it through Amazon, and after my additional compression test made today (still at 80 PSI), I am now convinced that I need to return it. The carb is also new and worked fine prior to me replacing the head and piston.
I'll tear it down tomorrow and send it out for a replacement.
I'll let you know how it goes with the replacement.
Thanks everyone for all your assistance!
 
AS promised, the results of the new piston and head;
Bottom line, 80psi compression test is not a good reading and obviously the problem.
Replaced the head and piston with a new set today and low @ behold, the unit fired up right away!
The new head and piston is producing 125psi compression, maybe a little low but I figured a little run-in will let the rings seat and should produce a higher PSI.
Thanks everyone for all your help!
 
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