Re: how to leak down test on 4 stroke?
Have to make sure that the cylinder your checking is on compression stroke at TDC (top dead center). Put finger over spark plug hole, crank engine over slowly until you feel pressure blow finger off hole. Now you are on compression stroke. Gently insert small screwdriver into hole until you lightly touch top of piston. Hand rotate engine until piston is at TDC. Now do your leak down test on that cylinder. Will have to repeat on all cylinders the same way. Hope this helps.
