Try it like this and tell us what you get,
Before making a compression test, run the engine until it is at normal operating temperature, ensure the batteries are fully charged and the starter system is in good working order, if it does not crank as fast as it should, the compression reading will be low, next blow the dirt from around the spark plugs with compressed air and remove the spark plugs, make sure the choke is closed and hold the throttle open, this is so the pistons can draw in a full charge of air on each intake stroke.