It is called a spanner wrench, there are many different designs and uses. Google “Yamaha outboard tilt and trim wrench” and switch it to images. Dealer can hook you up or ebay or you can make your own with the measurements from your unit. Sounds like some locktite should be added.
I have a heavy all Black Ranger cover for my 620. No probelms at all with any heat build up or any other issues, but black does show some dirt, but what color’s not going too.