The mower runs great and has 120# cranking compression.. After 3-5 minutes starts smoking.. hot or cold.. I thought oil ring. Just ask expert said no it's the intake valve seal.. replaced it and still smokes same.. breather and exhaust not pluged. I feel it has to be oil ring or cracked piston. Would like to find procedure to do ring job and what other parts I should change while apart. I used and they were spot on. Any suggestions?? Thank You.. Bruce--->