RE: Engine Seizes
Aug,
If the engine seizes while starting, the sleeve is apparently not growing fast enough, as the engine is beginning to run.
I had an OS.40FP in the past... The trick was to have the high-speed needle set lean enough, for the engine to 'instantly' reach its operating temperature; and the parts, their running dimensions.
The break-in procedure is clearly described [link=http://www.rcuniverse.com/forum/Tapered%2DBore_Engine_Break%2Din_%2D_Upgraded/m_1850473/tm.htm]right here[/link].
The dubious info regarding this procedure in the manual, should be regarded as such...
What is now happening, is as the engine is started up, the light piston is the first thing to increase in temperature and to expand; faster than can the nickel coated brass sleeve.
The fit of the piston in the vicinity of TDC, thus becomes excessively tight, causing the engine to grind to an halt, within a few revolutions...
If the mixture is set lean enough (yet richer than peak), the heating of the sleeve comes earlier, with the engine not stopping, but overcoming the temporary near-seizure...