It has been clearly stated that ---" spritzing fuel / oil mix into the top carburetor there is no change at all "----- This issue should be so easy to resolve !!
The knocking and lack of power is a concern.----Some will slam me for suggesting a compression test.-----Do yourself a favor and post the actual values you get from a compression test.
That would be correct.----See post #4----In my opinion it should not be hard to find where the issue is with this motor.---Sorry ---I can not be any further help on this one.