Black smoke on decelleration

[cansel kansu]

CR more like 9 to 1

ok, that was what I knew.
it was the unit conflict, you were talking about psi not bar...
so perfect reading should be 135 psi which is quite close to kenr427s result. maybe a bit lower than it should be, but can it be the reason of smoke?

 

[glider]

135 is rather low and indicates a loss of seal on the rings . It more than likely could be the problem here.

If you put just a small amount of oil in the cylinder and retry the compression test again, it will give you a better reading indicating the rings are worn.