Is the oil level proper? It should not effect the engine operation, anyway.
I am going to guess that it needs a new gasket/diaphragm under the carb. Pay close attention to how it come apart, and watch the location of the spring under the carb. Make sure it returns to the same location. That should resolve your problem. Good Luck, and please report back on your results. (You should be looking at less than $5.00, I would guess.)
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