compression question

[ModAfan]

I did a compression test yesterday. Cylinders one through four measured 60, 60, 45, 65 psi, respectively. When I inspected the sparkplugs, I found that plug #3 (cylinder measured 45 psi) had soot on one side of the ceramic cone. The other plugs had no soot on the ceramic.
Anyone know if there is any correlation between relatively low compression in a cylinder and soot on its sparkplug?
Plug #3 is second from left in photo.
Thanks

 

[Mitch//pa]

if a cylinder has low compression its not getting a complete fuel burn and can cause plug fowling..
do a leak down test to determine what maybe the cause

 

[Patrick L.]

I agree with Mitch.
Have you checked valve lash lately ?
Did adding a bit of oil in the cylinder change the compression reading ?