# Compression testing a BR420C Magnum



## Weesa20 (Jul 7, 2014)

Got a new compression tester for my B-day. Tested my Stihl BR420C Magnum backpack blower and it is only showing 70-80 PSI...runs pretty good though. Tested a couple of other machines and pushing 145+ PSI so I am pretty sure it is not the tester.

Wondering if it is the "C" parts on the blower? My understanding is that this has some sort of easy start feature, could this be making the compression read low during testing? I know it wouldn't run with only 70-80 PSI but it does...so what's up with it?


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## gunnusmc03 (Jul 12, 2014)

Don't these have a mechanical compression relief valve? It will be hard to comp test these if they do.


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