16 HP Briggs twin repair troubleshoot

[daveshoe]

I got an older briggs--appears to be a Vanguard style motor. one cylinder does not fire at very slow idle and the unburned residue aopears to have oil in the residue. Increasing RPM lights up the dead cylinder and there is not an excessive amount of blue smoke. Probably my first test is compression for the cylinder. My question is : Is there any circumstance that a motor does this that is valve train related ,or do I figure on a cylinder rebuild? The fact that the cylinder lights up at higher rpm suggests to me that pressure is bleeding out of the cylinder before it has a chance to fire at the lower RPM.

I am looking forward to your knowlegeable advice. If pulling the head would help with the troubleshoot, I can do it within two days.