My chain saw runs and pulls good if you can get it started, but sometimes it will not idle just stops. I have disassembled carb everything seems ok adjusting don't help much. I can push down the reed so it should be working but I am wondering if I have enough suction or compression to open the reed valve to let fuel in, can one use a compression tester and what is the mininum psi to open reed valve? Two biggest problems it will not idle and hard to get started it cuts good under load so that should elimanate fuel, air cleaner, sparkplug. I just wonder if it does not have enough compression would it not cut wood?