Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

I always mix my MMO 20/1 or 25/1 and have also run with no problems at 15/1.

I like having fresh oil coming out through the exhaust. 
This tells me with certainty that the engine is getting good cylinder lubrication which is critical with rubber O-rings on the pistons.

Jin provides extra O-rings with his engines however I have never needed to replace one.

Gil