We are working on a Generac portable generator. Wouldn't run initially. We had a bad fuel pump. Replaced fuel pump. Then while trying to start, it was pushing oil out of the valve cover. So we figured it was either out of time, or a blown head gasket. So we took the head off and noticed what appeared to be a spot between the combustion chamber and intake on the head gasket that looked like it could be the culprit. Got a new head gasket. Put it all back together. Adjusted the rocker arms to around .004 of an inch. Poured a little bit of True Fuel in the intake on top of the carburetor. It will run,if every few seconds I pour a bit of fuel in the top of the carburetor. What could it be.