i have done it by hand and by the starter and the results where night and day. the readings that i took on the starter where much higher than the ones done by hand. my gauge also does not have a valve on it but the gauge it self saves the highest reading then i need to push a button to release the pressure. One of the times i spun it by hand i was only seeing 30psi and it turned out the timing was off. i had the crank key way at 3oclock and not 2 oclock on the RM timing set