New engine has loss of compression

I don't have any mineral spirits, I will get some tomorrow and then test that way.

Also I was looking at the valves, I understand that an exhaust valve would be sooty, but shouldn't intake valves be clean? Number 4 (issue cylinder is all full of soot around and under the valve, number 2 is nice and clean, and the last two are kinda sooty, but cleaner than 4.