Small Engines (Lawn Mowers, etc.): 18hp backfiring through muffler, right cylinder, compression check

Question
John this is Rick again with a follow up on my mower, Again I have 18hp OHV intex engine model number 407777 type 0128E1. Since I have talked to you Sunday I ran another compression check with the right side at 135in and the left side at 105in, When I squirt a few drops of oil in the weak cylinder I now get a reading of 135 also. I tried this several times with the same results. After the oil had been used up in the cylinder and I ran the check again, it then again read 105 if this helps in any way. As for as the head being warped just inspecting it and cleaning the carbon off it, it looked ok. The exhaust and intake valves were set at about.006. I still am waiting on the new carb. Thanks again for your help.
Rick

Answer
Hi Rick:

From this E-Mail. it Sounds like a Cracked/Broken Compression Ring or a Loose Valve Seat in the Block is Causing the Compression Loss on the Left Cylinder. I have Seen this Several Times, but it is Not that Common. I have an Engine that Came Into the Shop Yesterday that has the Same Complaint as yours. Randy Performed the Usual Diagnostics and Located the Problem on the Right Cylinder. He will Finish the Diagnostic Today. Thanks for that Update. I will Follow Up Later Today.

Respectfully

John