After countless hard runs with the new Landmax and its GS21R engine, my temp gun recorded temperatures in the 250-degree F range at the glow plug. That's 20-30 degrees hotter than most 21 engines typically run, but not nearly as hot as the older GS21. And although the GS21R has a relatively mild midrange powerband, it really screams on the top end and will idle all day long. Tip your hat to the redesigned cooling head for the longer engine life and better performance it provides.