You need to know that you are on TDC. It has to be, or when you start putting in the air, it'll either run over you, or back over you. If you can get someone to hold the brake, it makes it easier. Open the butterflys, so you can listen in the intake, as well as the exhaust, and take off one of your breathers, so you can tell where the air is leaking. If it hasn't been run for a while, there may be enough fuzz on the valves to hold them open, that's the reason to open up everything, so you can tell where it is leaking, even if it's only 5%, it's nice to know where!. If youre not getting any pressure on the line side of the gauge, listen to it, it may only be a "fuzzy" valve, which you can ck, by a light tap on the rocker, which ever is leaking. Some guys get worried at 20%, I worry at anything over 5%, but shouldn't, I won't tear one down to find it, but I'll watch it. Good luck! Bob