One pump; one pump only.
Which test we perform determines the procedure used. Three procedures are described and each test has a different purpose.
But keep in mind when the engine is running it only gets one pump per cycle.
Running compression test: A decent way to estimate volumetric efficiency (VE). This is not technically a compression test.
Install a screw in gauge into on cylinder and run the engine at idle. Now read the max pressure for each compression stroke. “Burp” the pressure out of the gauge after each stroke. Average 5 readings. There are no published specs for this test. Compare cylinders to each other. Normal readings are 75 psi. The normal range is 50 to 100.
Cranking compression tests
Wide open throttle. Battery fully charged, ignition disabled. Fuel disabled.
First pump test: Same method as the running test, burp after each pump. The reading should be at least one half of the reading of the max compression test listed below. Depending on compression ratio and carbon deposit volume. I find this test gives a better indication of cylinder leakage due to worn cylinders and leaking valves because this value is the only one the cylinder actually sees.
Max compression test: The traditional test. I pump till max pressure is reached. I count pumps, the more it takes the more likely leaks are present. Others will have a number of pumps they prefer. Average reading for a normally aspirated gas engine is 180psi. 200 plus could mean excess carbon deposits. Low means leaks.