Hi Darryl, Remove the muffler and remove the valve cover. In there you'll find the valves. Check the clearances at TDC, the valve clearances will more than likely be closed up causing your valve to not remain closed lomg enough thus causing your low compression issues. Valve clearances are (Inlet: 0.005-0.007, Exhaust:0.007-0.009 inches)
As for the vibration issue, check the crank by spinning the blade and see if it is spinning true, keep your eye on the bolt in the centre to see if it deviates away from centre at all as it spins around.
