I have a slightly used 3.2 Sachs style engine on my WH Edge. It has a lot of power, but blubbers at mid range. If I roll to inverted as it is blubbering, it instantly goes away. It totally clears up. Roll back to right side up and it blubbers again. I can lean it to the max on high and low needles and it still does this. Does anyone have suggestions? Thanks!