Starter direction for methanol engine

I am having a small 2.5cc methanol 2-stroke engine that I am building an electric starter mechanism for. From my research I was under the impression that for a 2-stroke engine like the one that I have which is completely mechanical using a port for fuel intake it should not matter what direction I am starting the engine, it will just continue to move in that direction.

Image of the engine:

In order to make sure my DC motor used to start the engine is not suddenly "powered" by the much faster methanol engine I am using a one way bearing on the gear connected to the methanol engine. When I did a test run I could hear the methanol engine engage (due to the noise), but it cut out practically immediately afterwards and I could see kinda heavy abrasion on the gear of the DC motor (it is 3d printed, not some metal gear). I am getting the feeling that the methanol engine starts but wants to turn into the opposite direction of how it got started and then dies out pretty quickly because of the resistance.

This goes contrary to my believe that these 2-stroke engines should be able to run in any direction. What are the parameters that influence this for an engine and how would I go about determining that direction except ruining my starter gear and do it empirically? How does this work with a pull start, i.e. how do they ensure that the motor never engages in the other direction?