I installed a wet gauge today to check the real op. I did not pay a whole lot of attention to the gauge when I bought it and wish I'd bought another one because this one is a 100 lb gauge and is very
insensitive at low readings.

At any rate, when I first start it up the pressure climbs to about 25 lbs at idle, then it falls to about 0 on the gauge after a few minutes. The dang gauge is probably useless at low reading though.

What do other peoples op readings start out at with cold engine?

The only thing that's left is that relief valve, I suppose it could be malfunctioning, but I already cleaned it once.

When I first started it up after installing the gauge, I was happy to see that the pressure was respectable, I went away for ten minutes and came back and the pressure was about 4-5 on the gauge, a 5
minute run brought it down to 0. In the opinion of the list gurus, any chance that this is a relief valve issue? I thought I'd start it up and watch that gauge while idling, to see if it fell suddenly
or gradually. If it fell gradually, it would logically be a true pressure drop, if it fell kind of suddenly, it might be the valve letting go at an inappropriate time?

About near the end of this one way or another.

mark...