Kid and his buddy decided my lawnmower wasn't running right so they took it apart this past winter and made an adjustment to correct a timing issue???? I wasn't having problems before they did this. It still runs fine except it uses approx 6 ounces of oil every tank of gas. If the mower gets tilted with muffler down, it blows white/blue smoke. Heavier the tilt the heavier the smoke. Can anyone tell me what they didn't put back together correctly? Seals or other components?