The engine will run for some time with the OMP not doing anything. Some of my gifted engines have had the hoses broken off. There will be a slight amount of oil added from the oil scrapers on the rotor sides not being perfect. The scrapers will also scrape off unburned fuel and mix it with the crankcase oil. High oil temps will remove most of that fuel through the breather. Note that crankcase breather gases are explosive. A good reason to smell the dipstick when ever it is out.

 

So, as the engine wears out the scrapers it starts needing less top oil.

 

The only downside to injecting into the housings is poor distribution. It leaves a boat wake looking stain on the chrome. So, it looks to me like some of that microscopic amount of oil is discarded without helping anyone. It seems to me that the best case is the premix. If I were to use the OMP, I would drop it all in behind the Throttle Body, or into each throat on a carb. Or if you are a purist, into the float bowl.  

 

Years ago synthetic crank case oil was specifically not recommended by Mazda. (because of gumming)

 

Lynn E. Hanover

 

 

 

 

So it would also seem to me that using the OMP with 2-cycle oil in this scenario is significantly different than pre-mix.  But is it as effective, more effective, or worse??