Hi NormK,
was this after doing any work on the engine?
Could you try an oval two blade carrier on your next conversion? Is a lathe essential for all of them such as the 16" Aldi mower you did?
I have read one review where their self propelled system stopped working, leaving a heavy mower to push around.
It seems the much needed momentum of a blade disc might well be the magic bullet to many of the bar bladed mowers out there. A good use for all the excess blade carriers and catchers from rusted away steel Victas out there.