I have a new o.s 50sx and just finished my new profile. The problem is I will not be able to fly for a cople months, and I want to get a couple flights in beforehand. So my question is will it harm the engine if it is stored before it is fully broken in. I will follow the break in procedure, but I have been told that it may quite a bit of running to seat the ring. I will probably be able to run five 6oz tanks through the engine on the ground before flight, and then maybe 3 flights. If I run all the fuel out and use after run oil will the engine be ok to store for a couple of months?

Fly4fun,


This is a ringed ABN engine, with a parallel bore.
It needs a gentle, very rich, four-cycling initial break-in.
Gentler, richer and longer than described in the OS manual, is the way to go.

Do not dare to follow [link=http://www.rcuniverse.com/forum/m_1850473/anchors_1850473/mpage_1/key_break%252Din%252Ctapered%252Dbore/anchor/tm.htm#1850473]this RCU thread[/link], since it is designed for non-ringed, tapered-bore engines (which the OS.50SX is not), even if someone here mistakenly tells you to, as it will harm this engine.

I used a very rich run in period on my 50sx also! I started with the needle set almost 3 and 1/2 turns out and slowly wound it in. I ran 2 8Oz tanks (at 3 and 1/2 turns out) through the engine, then after each subsequent tank full I would wind the needle in 1/8 of a turn. Use various rpm settings also and try not to hold any given rpm for too long. Also allow the engine to cool fully between tanks. Yes there is not problem "that I know of" in storing a half run in engine for a while as long as you use after run oil.