Have you lost that tiny shiny washer that was attached to the motor shaft? Now your props wobble and won't sit flat?

Well you could hunt around for the perfect fit washer - we tried but nothing 'perfect' found yet, let you know when we do.

But what we have started to do is file a groove in the prop hub to accommodate the two o-ring screws. We use a 'rat-tail' file like a small chainsaw file. Simply file down evenly on both sides to the internal flat surface. Done!