I replaced the poppit valve on a 2003 200HP OX66 engine to the new style. I've got better pressure at low RPMs (8-10 when cold and 4-6 when warm) but now at WOT I'm getting up to 28-29 psi. With the old style (not too dirty) I was getting 4 (maybe) at idle and 20 or so at WOT. I'd attribute much of this to the new spring that was also installed but how high is too high before I'd have to worry about the water jacket gaskets reaching their limit?
