I would find a Juki or industrial machine repairman. That serger was built by Juki for Babylock. I am suspect of the diagnoses of timing being off. She would have had to run something pretty thick through the old girl before the timing went out. Those machines were built on an industrial platform. If I were to guess I would say improper threading or maybe a bent looper, timing wouldn't make my radar. Another thing that can really affect the stitch quality on a serger is a dull knife.