Yeah, that makes sense. One article I read about gas-engine knocking talked about a "controlled burn/expansion" versus a "rapid explosion" in the cylinder--the latter causing knocking.Ken, as I have recently half-watched a youtube video about diesels vs gasoline engines, I am now a certified online diesel mechanic. It could be that if something in the cylinder is already hot enough to start the combustion earlier than desirable, the very very first fuel coming out of the injectors might light before the entire spurt of fuel has been injected, is compressed, and ready to go. this would probably create a noisier/rougher shockwave than if everything was sub-second perfectly running.
I think we're all (or, many of us) becoming youtube and EYO certified experts now. Makes me wonder how the hell the average guy knew how to maintain his boat back in the 80s-90s????