Got a OS SF 46 ringed motor with a 4D carb. I have an instruction sheet for the carb that gives initial setup for the lowspeed/ide screw, but how many turns out should I start with the high speed needle? Thanks in advance for any help.

Try 2 1/2 or so. Thats fairly rich but it should start. Lean if from there as you break in. If burbles and won't stay running go a few clicks at a time till it stays running.

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.

Just open it up a bunch (3'ish turns) and fire it up. It will start out really rich so leave the glow ignitor on as you lean it out.