Found the problem
So,
after 2 years of searching for the problem, here was the issue.
We opened the engine and checked for worn cam lobes, heavier pistons, all that jazz... The carb was rebuilt. Engine mounts replaced. other stuff I cant even remember...
In the end, I went to flip the propeller on another Cessna 150 and noticed that the impulse coupling fired with the prop at 1 o'clock and 7 o'clock looking aft. Mine fired at 3 and 9 o'clock. Well folks that's all I needed. Reinstalled the prop correctly and its a new engine.
The funny part is - I had two certified mechanics tell me that the prop was installed correctly a year ago...
Just wanted to relay the info after 2 years of searching this horror story.
Happy Flying