It seems highly likely the engine has the Intek disease, Pinelli (blown head gasket). We need a way to confirm that it is blown. You may be able to check this by removing the oil filler cap with the engine running, and seeing whether it is puffing out air and oil spray with a fair amount of vigour. Note though that the fuel pump won't work with the filler cap removed, so you will have to do this in less time than it takes the carburetor float bowl to empty. If it seems to be puffing, you could probably confirm the problem with a compression test. Also, look at the breather system: if oil is passing through the breather into the carburetor air intake, that is another sign of blow-by, which in the case of an Intek is nearly always due to gasket failure.
Inteks usually blow the head gasket from the combustion chamber into the pushrod cavity. The damage is not always visible by looking at the gasket, cylinder head, or top face of cylinder, unfortunately. There is a good chance that replacing the gasket - carefully - will cure both your problems though, if you find supporting evidence of leakage and/or crankcase pressure.
