I just put my boat back in service today, and no problems . The ball valves are working well for draining the block and steering cooler. Made life easy last fall winterizing and no leaks . I put a bit of silicone spray in the valves with a spray straw each time they sit for the winter. No drips...
Not uncommon for a coil to get hot, but if it burned you then too hot. May have a short in it. What Scott said is the reason I decided not to go that direction.