I purchased a ProMac 8200 off eBay. It does not have a compression release and it cranks very easily. In fact you can turn the flywheel with your hand and you can barely feel the compression. On the other hand, I have a ProMac 700 and it is very difficult to pull the starter cord unless you use the decompression valve. You can turn the flywheel on the PM 700 with your hand but it will move the saw and it builds up a lot of resistance way before top dead center. It feels like it has more compression with the valve open than the PM 8200 has. However, using the same new chain on a new 28" sprocket bar in 36" red oak the PM 8200 outsaws the PM 700 maybe 20% faster (just made 2 cuts first one with the PM 8200 then one with the PM 700 - so the PM 8200 had the advantage of the freshest chain but that shouldn't be too much of an advantage; and yes the PM 700 seemed to be running right). I thought the 12cc difference would be effectively cancelled out by the huge compression difference. Long introduction to how much psi equals "good compression" as I see these terms tossed about on this site? If I can find a gauge to borrow, I'll measure the two. Replies appreciated.:newbie: