I just got my ST-75 ringed engine. This will be the first engine I break-in. I have been using a Evo-46, that was already broken in at the factory. I purchased a break-in engine stand. This engine is new from Italy (two yrs old, never been started). I have read various info on breaking in engines both ringed and ABC. Any thoughts, tips, and or wisdom would be appreciated. Thanks!

Michael

Michael,

I always break an engine in on a test stand.

The ST G-75 is a ringed piston design, not an ABC/ABN. So the break-in technique must initially be a very rich, cold, four-cycling, low RPM method.

The first tank, or two (10-20 minutes) must be run with the glow driver connected, at a very rich mixture setting. The head must be only warm to the touch. Not hot. Not scalding.

The next 2-3 tanks (20-30 minutes) must be a warmer four-cycle, without the glow driver. The entire four-cycling, rich part of the break-in is done on the stand.

Afterward, it must be run at a rich two-cycle, and can be flown.
After about 90 minutes total time, you can adjust it carefully to full RPM (200 down from max, with the nose straight up).

All the quirks of a new engine are a potential hazard to the wellbeing of the model and the engine. I have seen engine mounts and lugs break in an attempt to start a new engine in a plane, engines getting burnt, because the fuel line routing was not seen to be wrong, runaway models....

Good luck.

You have already seen everything here before....

Darzeelon is correct. 100% so.

No point in opening another string of 500 "thoughts" on how to do it. He is correct.

PS: Check the archives a bit...this issue has been hashed over 12,000 times in the past month.

Good Luck...you'll like the engine!

'Race