RE: Need OS SF46 help
JD,
It depends on the fuel.
If you use 5% nitro, the normal running position is about 1.25 turns open.
Break-in is done much richer, as this engine has a cast iron ring running in a steel sleeve.
Begin with several (10?) short, rich bursts of 10-30 seconds, with complete cooling between them.
Then go to full tanks.
Keep it four-cycling rich for at least 30 minutes, before peaking it slowly.
You should do the first 3 tanks on the ground and later, lean it a bit (still four-cycling, with an occassional burst of two-cycle) and fly the rest of the break-in. It will be ready to peak-out after about 2 hours.