I got a used HRT216SDA mower this fall, and the drive belt started falling off. I replaced it with a new one and it still only stays on for a few feet of mowing.
Researching on this site, I found mention of Honda stopper kit 06915-VG4-395, said to be three washers and a stopper collar, and ordered it.
When it came yesterday it seems to have been tampered with at Honda, kit has only 3 washers in it and one of the two official-looking paper stickers on it covers up a big hole where someone pushed a part, I assume the missing stopper collar, out of the plastic bag. The sticker covering the hole has a bar code, the part number and name, and the designation OB-598 on it. It is thoroughly stuck down all around but plainly covers a hole in the bag, as I said.
I wonder just what is this stopper kit and how assembled. I found discussion of it on this forum before ordering it but am having trouble re-discovering it.