Review on Professional Automotive Tester Cylinder Compression by Jose Miller

I have compared the compression results of 3 chainsaws with a well known 'good' brand compression tester and this device failed miserably. My saws are running at 150, 165 and 205 psi on a known good tester which is consistent with known factory data for their respective chainsaw models in good condition. This tester was wrong. As long as you know it's not an accurate representation of PSI, I think it can be used. For example, my Dolmar 7900 pump pumps out at 165psi. This tester showed @ 120 psi. This saw would hardly work at such low compression. The piston and cylinder are in excellent condition since I disassembled the saw.