Noticed this had popped up again. As closure for the issue noted in my January 2022 post, the problem turned out to be a combination of not enough “play” in the engine harness and a bad drawbar. The Forum sponsor from whom the engine was purchased, was able to perform a quick warranty repair and the engine performs flawlessly now.
And confirming Vernon’s response to Macado immediately above, this is a Railking engine.
Curt