[Bob Mulry]

In the old days GM had a fix for deposits on the back of valves and in the combustion chamber........

The fix was to bead blast the back of the valve and the combustion chamber with walnut shells.......

Combustion chamber and the runners got vacuumed out and the manifolds & spark plugs reinstalled.....

It was the last attempted fix before cylinder head removal....

It seemed to work....

Since it appears that these generators suffer from the same type of problem it might be worth trying first before removing the head???????????