Hi Shannath15
As Mowerfreak said, 125's are marvelous engines
One thing though (and Mowerfreak or others correct me if I'm wrong), I remember the mixture for the Imperials was 50:1 (100 mL 2 stroke oil per 5L) due to a low compression head (99.999% sure of this).
Running 25:1 won't kill it though - but straight fuel will. If in doubt, Bunnings have a Ozito mixing bottle ($8), very good and easy to use. Never mix fuel & oil straight into the tank - too easy to forget.
And don't use E10.
Have you checked the air filter to ensure it hasnt decayed and is being slowly ingested by the engine?
These are really good machines, very simple.
Even though you say you don't know much about it, knowing it is a 2 stroke is surprisingly overlooked in this day and age, well done for not learning the hard way like many people do.
Regards
Tyler
