That is all it needs to do. You disconnect the wiring to the ignition, remove all of the spark plugs, block the throttle open and then install the compression gauge. Now turn the engine over until the compression gauge stops rising and write down that pressure. Then move to the next cylinder and repeat the process.
When you have all 4 pressures then you can compare them. Say you find the first cylinder has 140 psi, the next 130, the next 60 and the last one has 30. That would not be a good set of numbers. Ideally you want them all within 10 percent of each other from high to low. So if the high pressure was 120 you want the lowest to be no lower than about 110 or so with the other 2 falling in that range.
Tuesday, December 29th, 2020 AT 9:11 AM