i have a new TT 61 pro. i have run 1 tank (12 oz.) of 15% nitro through at 3/4 to full throttle. is it broke in enough to fly or should i run more through it. also am i correct in breaking in at that throttle setting.

It's not breoken in yet. But you should put it in the air as soon as you get the needles set. Do you have it adjusted yet? If you do, watch carefully about not having any lean runs.

Enjoy,

Jim

I agree... Make sure your needles are set for reliable running plus a bit rich and go fly.

I would run about a half a tank more, then set the needles on the rich side but with a good transition. Put it on the plane (if not already). Check the needle settings, set the high speed on the rich side (about 500 to 600 RPM below peak) and go fly. It won't be truely broke in till you run 1/2 to a gallon of fuel in it. You will notice the engine getting stronger with each run till it is.

I run mine on the ground till the exhaust oil doesn't show metallic particles or black residue. I figure its about ready to fly then. Then I set the idle as well as I can, fly it, adjust it, fly it, etc until I don't have any more gain of RPM with it.

I consider an engine to be broken in when the following occurs:

Engine can maintain a mixture setting at wide open throttle that is 400 rpm shy of max lean rpm without overheating or wavering.

and

Engine maintains a smooth reliable idle and transitions to full throttle without any problems.

If this occurs after running an engine for 1 tank or 5 tanks is dependent on many factors that I won't go into.

If you engine is oversized for your plane there is nothing wrong with a break in flight. Just be warned that you should fly at full throttle the entire time and that if you go to idle you may lose your engine. I usually richen my mixtures just past the 4-2 stroke point and go fly realizing that power is marginal and engine is not reliable if slowed down below wide open throttle. I usually deadstick her in for a landing when engine runs out of fuel.