Yes, these engines quite often start backwards. The cause is because the engine is flooded. When you are priming the engine you are getting too much fuel in the cylinder. The cure is to get less fuel in the engine when you are priming it. Here's what I do. With the glow driver OFF of the glow plug open the throttle wide open. Cover the carb mouth, or the end of the muffler if you can't get to the carb, and turn the engine over counterclockwise by hand. You should see fuel being pulled up the fuel tube each time the engine turns over. When the fuel reaches the carb turn it over 2-4 more times. Then close the throttle to idle, put the glow driver on, and start the engine. The amount you turn it after the fuel reaches the carb can be adjusted. If it's still starting backwards reduce the number of turns. If you don't have enough fuel add a turn or two.

Ken