Steve-o... I don't think I'm following...

First, it sounds like you know the engine is running backwars only because the started was turning backwards -- but glow engines often backfire or just kick against compression and end up running in the direction opposite that of the starter, especially if the glow plug is too hot. (For gas engines, a lot of them are started by intentionally flipping backward into the compression and letting the prop bounce back hard enough to start in the forward direction... and I have seen the same technique used in hand starting larger glow engines as well.) So you can't really tell engine direction just by starter direction.

And on the other item you say that, "If you look at a prop, spin it slowly backwards, you will see ( at least on a 7.5" pitch) that it still screws into the air." If you're saying that your particular prop screws into the air in a forward direction when you turn it "backwards", sure, that could well be.

But it almost sounded like you meant that it would screw into the air in a forward direction when you turn it in either the clockwise or counterclockwise direction... if that were possible, then a bolt could be made the same way to go always in to a nut no matter which direction you turn it. That can't be (at least not within the rules established by what physics courses I've had).

So, I'm still a llittle lost by all of this, but I'm glad it works for you.