Stihl BR420 compression

[lwcmattlifter]

What's the min acceptable compression psi?

[mowermankevin]

It just depends on the machine, some run good down to 70-75 lbs, I've got one the owner and I can't believe is still running at a forever rate of 65 lbs, never fails to start, but it's a miracle old machine. When they get this way, they have a lot of RPM's and not much power.

[topsites]

Honestly, 100.
You might can do with 90, but like the man said the lower it goes the more you end up with something that kinda runs.
Forget what is new, I think 120?
Not sure but 100 is acceptable, I just don't recommend much lower, 100 is an easy to remember, good as an all-around kind of a figure.