I am helping a neighbor with his Nexstar soon and have some basic setup questions relating to the OS 46 that comes with it. My only experience with breaking in/ tuning engines are with OS 50 hyper heli motors. Does the engine on the OS 46 come ready to fly? What adjustments to the low and high end needle may be necessary? Thanks for all the advice!

OS 42?

I think he means OS 46 FXI. that's what ships on the Nexstar.

You can download and view the manual for this plane here:
http://manuals.hobbico.com/hca/hcaa17-manual.pdf

They say the engine is pre-run at the factory. This doesn't mean that it's broken in. In my experience with this engines, if you run them rich for the first 10 tanks or so you'll be fine. Then lean it out so you have the faintest smoke trial in the exhaust and the engine will last for a very long time.

Ken
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Yeah, that's the engine I had on mine. I was wondering if maybe he swapped it for something yet unknown.

CGr.

It's an OS bearing engine! It will run well at a wide spectrum of needle settings. As RCKen states run her good and rich for a few good tanks to match up the metals inside and let her rip.

Whoops, 46!

Ok... no sweat

ready to fly.....yes after you break it in.....with at least a few tanks through it te first very rich then leaning it as you go......remember in flight you want to see a smoke trail.

And, above all, don't be afraid to go full throttle with the break-in process with that extra rich setting. It should be blubbery rich and go to full throttle and held there for a while (see manual), then leaned out for about 10 seconds, back to idle for a minute to cool down, then back to full throttle and blubber rich.

Some people baby the engines and don't take them to full throttle during break in. That does not allow the engines to "seat in" properly at full throttle thus the overall performance after break-in may suffer.

CGr.

Here's what the OS manual says about breakin on that engine:

"...only a very short and simple running-in procedure is required and can be carried out with the engine installed in the
model. For the first few flights with a new engine i.e. while the engine is being run-in set the needlevalve
for a slightly rich mixture not excessively rich as this may result in poor throttle response and cause
the engine to stope. About one-quarter turn open from the nomal setting will usually suffice.

It is expected that I will have to adjust the high end needle?

Yes, that is how you adjust the mixture so the engine will run lean or rich. With the model running at full throttle, adjust the needle so the engine runs it's fastest and smoothest, somewhere around one to two turns out from all the way in ( don't tighten it too much when it goes all the way in). Next turn it out counter clockwise a little more until the engine is running a little rich, where the exhaust becomes more visible and the engine gurgles a little.

Sorry I meant the low end needle, the one where you have to use a small flat head to adjust.

after 5-10 tanks it becomes a bit rich and unresponsive, then the low end needs to be leaned out a bit, also that little plastic limiter on the high speed needle can come off right away they are often times set improperly at the factory, and just get in the way.

the low speed needle is in the end of the carb barrel, needs very little adjustment to get it running properly after the first few tanks

thats not true about seating in.........run it as your going to fly it......it has a warranty!!!

I believe he was suggesting thatone run it full throttle during the break in period to help seat the ring...and this is correct. This is the same as running it as you're going to fly it.

there's no ring in the OS 46fxi, the engine runs fine out of the box, just run it rich for a few tanks and it will be fine there great little engines.

If you guys don't have it, just download the manual from here:

http://manuals.hobbico.com/hca/hcaa17-engine-manual.pdf

And follow the instructions to properly adjust both neddles for and after the break-in period.

Regards!