The hottest area you tested are the intake covers. They have no water jacket and seem to get pretty hot on those series 9.9/15 hp motors. For example, on my 1992 15hp, it has a 7000rpm WOT max and I run it at about 6800 rpms wide open....after a run down the lake at WOT, the head and top of the block are hovering around 145 deg (which is close to the thermostat setting), the exhaust cover is 10 deg or so cooler, but the intake covers are ~180 deg. My 1982 9.9 has similar readings after running it WOT (5500 rpms) but scaled down temps a bit due to lower rpms I guess.
