Cold engine clattering (300E) upon startup prevented if...
 

I turn the ignition to the start position, then back. If I do this 2-3-4 times, the engine doesn't "clatter" upon cold start. If I don't, and start engine first try, I get the clattering until oil pressure rises.

Anyone have a clue what's at play here? It appears as if I'm "priming" something ... but nonetheless am befuddled.

TIA all! ;)