125 should be fine. You might want to check it again to make sure you still have 125, soulds like you overheated and boiled over. You need compression, fuel, and spark for an engine to run. If you have spark, we are pretty sure you have ok compression, fuel is not getting there. Clean your pilot jets. When I say clean them, I mean take them out, blow compressed air through each pilot, and make sure you can see light through them. Make sure your float bowls are on the correct carb when you put them back together. In the bottom of the bowls they are labeled 1-1, and 1-2. 1-1 goes on choke side carb. If not, choke won't work properly and you may kick it over 15,20,25 times before it will start. If you did indeed boil over, you should change the coolant and figure out why it overheated. Are you jetted right, impeller intact, maybe just haven't changed the coolant in a while.... Let us know what you find after all of this.