i have searched the engine forum for this but no luck.question is breaking in a os 40 la where is the needle valve setting i ran it almost out for the engine to start i have been told that to screw it all the way in then back out three complete turns does this sound about right yes i have help at the feild but would like to try and break the engine in before hand thanks mike

armyrcer,

I'm have a 40 LA and i'm reading the manual right now. It says the following:

Start the engine and with the throttle full open, open the neelde an extra half turn. When you first start the engine, open the neddle 2.5 turns.

Theirs your answer. hope this could be of any help.

Airplane_boy

I too, have an os40 LA. I just broke it in last week and when I read 2.5 turns from the previous reply I read my book. Mine says "open the needle valve 1.5 turns(for 40,46LA) in the direction of the arrow(which is open), from the closed position." I'm not sure what the last guy meant, but this is what mine says. Hope it helps. I can't hurt which one you use, if you open it 2.5 turns, you'll just run it rich, and I don't think that'll hurt anything.

rich is dandy fine!!!
go 2.5, start closing after the 3-4 tank, fly a little rich for at leat 8 more!!
after 12-15 tanks it will be ready to work and last for a long time!

From what my dad and I have read, You should probally run your engine kinda rich on the first 5 runs. Then you will get all of the parts greasesd pretty well. After that, you can set the needle where you want. Hope I could Help.

Airplane_boy

Just remember running too lean will kill an engine no matter how it is broken in. After it is broke in, set it so that you audibly drop RPM's (on the rich side) As your tank drains, it will lean out some anyway.

.armyrcer
Seems like you got all the good info on that OS 40.
I ran mine very rich.
After several flights I did lean it a bit but it keeps puffing out the smoke but it idles so darn smooth I left it and now have over 20 hours on it.
I read on another thread where most guys elected not to run rich.
All I can say is mine idles so slow it does not move the plane on a hard surface and never stalls.
Running 10X6 prop with it.
Great little work horse

thank you for all the help and info mike

.
Mike,
This is the best place for hep.
Many experts here that know engines and planes I never heard of.
Have fun flying

You can start @ 2.5 turns, but if you want the engine to give you the most hp in the future do not run too rich on the first runs.
ABC non ringed ngines (such as the LA's) are best broken in by bringing the up to operating temperature as soon as posible.
So if it fires up, leave it rich for about 30 seconds and then start leaning it (DO NOT OVERLEAN), a quick way to see where you stand is to pinch the fuel line between the tank and the remote valve, if you pinch the line and the revs go up (lean) you're OK if the revs do not change or go down you're too lean.