MDS 61 Break-In
The MDS 68 (should be same/similar carb on 61) has an initial setting of 2 1/2 turns open on both needles. Recommended fuel is 10-15% nitro. My preference is 5-10% nitro and a hot plug .... the OS F 4 cycle plug actually works very well. An idle bar plug is good for break-in. Use the "pinch test" (search forum) to set the low end needle. After break-in set high needle at 300rpm reduction (richer) than peak. It's an engine that requires a rather lengthy break-in .... a gallon of fuel? Break-in prop for a 58 is 11 X 7 and 68 is a 11 X 8 ....