I know I should know this but just got a leakdown tester. What is a normal % of leakdown considered to be max leakage that still indicate a good cylinder? The 10T502 I working has been eating dust for a while and has a 35% leakage rate pass the rings.. It seem that I remember reading that 20% was considered the max allowable. Of the SM is setup using the Briggs tester and and the one I got only needs 12 psi instead of the high pressure that the Briggs unit uses to set the gauge.
Now when I pull the head the piston is covered in wet oil on the carbon and the cylinder has quite a bit wear. Now it might just might be that diaphragm on the carburetor may be sucking excess fuel too as it emmitting black exhaust. Its diaphragm is pull in at the one of the fuel pump flaps so that may that source of the problem.
Just looking a for some thoughts as it has about 5 yrs since I work on a L head push mower