I just did this to my RC-10. Same set-up as you, except I needed a 13mm socket. Here's the problem:

You need to fix the one-way bearing in the socket some how, as otherwise it will stay on the engine shaft when you pull the drill away. The problems with that should be obvious.

Another bad deal is that I used three different adapters to hook everything together. As long as the torrington bearing was 'loose' in the socket, the slight wobble/runout caused by the mis-matched parts was no biggee. But once the bearing was "locked" into the socket (I used PFM), it now had a hell of a strain on it due to not running true. Those torrington bearings in the recoil starters are not the best quality; it was apparent that this set-up would not last long.

So I bit the bullet and bough a Yank Eliminator. Making your own systems is fun, and that's what modeling is all about. But sometimes you're better off just plunking down the cash...

Assuming you're getting fuel and fire, sounds like you need a faster drill, pal.

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