what is the best way to run in such an engine,
and shuld i chaneg to ss rear bearing first
thanks all and mary xmas

g.vardi

I have 2 OS 140 RXs. The break in is pretty straight forward, as per the manual.
The origional rear bearing should be good for about 100 flights, then change to the 140RX- FI bearing (part # 29430010)
Use an OS-F plug and start with a 16x12 APC prop. Set the pipe long - about 22". I use 15% nitro fuel (Power Master with 18% oil - castor and synthetic blend). Open the needle 2 and 1/2 turns. Start the engine and slowly open the throttle to wide open, very rich - very smokey. If it is too rich slowly close the needle so that it will run WOT. Then slowly close the needle to bring the revs up for 30 second bursts, then open the needle again to the starting possition. Run just 3 to 5 minutes, shut it down and let it cool. Repeat the process for 3 tanks eventually closing the needle to full revs (8,200 RPM) and then back off 2-3 clicks, make sure there is pleanty of smoke.
Now set the idle at 1,500 RPM. Check the mid range tansition from idle. The low end needle ajustment should be OK at least for the first few flights and then only need a slight (1/8 of turn) lean. That completes the basic break in. After that you will be looking for a smooth mid range transition in flight. Much depends on the pipe you are using. You should be aiming for a about 8,200 RPM on an APC 16x13W, a 17x12 or a 15x13 3 blade. Some like a 4 blade. Search here for some good threads on 140 RX props and the 140 in general.
For any problems or questions come back to RCU and ask. There are people here with loads of experience on the 140RX.
For my money its still the most reliable, hastle free pattern engine available. I hope the 160FX I am moving on to is as good.

Good luck and a Happy Christmas!

Change the bearing first. It's easy and I've had the stock one's go bad within 10 flights.

Your going to love this motor..

Good advise. Also, if you run into problems with the mid range, you might want to consider the Mintor 3m 140 twin plug head.

Definitely go with a dual plug head!! Great advice.. This was my favorite motor until it met it's demise last year.
I would get another but I'm electric now. I miss it though...

thank u all
i'll use cool power 10%nitro 18% mv oil,os pipe ,17/12 apc
that is for now,
it is going to be used on a ca models eclipse 2 that im in the-
midel of cnstraction

Pardon my ignorance, but this is my first experience with the OS140RX (coming from four stroke to a Webra 160 to the RX now...) The manual doesn't say how to adjust the low end needle. Which side is lean and which is rich (CW or CCW)?

CW is leaner. It is fairly sensitive, small adjustments, a little at a time, the whole idle adjustment only turns about 1/4 turn stop to stop. Most of my engines seem to end up with the idle adjustment just CW of 'centered'. You want to be able to run the idle as rich as possible and still get a good transition. The richer the idle, the faster the motor will drop to low idle when throttling down.

Don

To add a bit on Don's comments, rich running at idle, mid range and WOT is a must if you want bearing life and consistent engine running over the long run. That is true for any engine not just the OS. That requires proper pipe set-up and good fuel with 15-20% nitro and plenty of oil, and not going too far on the idle mix adjuster. A hot plug such as the OSF type, makes for a fine combination

MattK

Ditto all of the above.

Don't be afraid to run as large of prop as a 19x10 Mejlik or 18.1x10 W APC once it is broken in. I think there is a APC 18.5x9.5 available now also. Mike Harrison has been using one. With a long enough pipe setting it will run fine, will turn about 75-7800 RPms on the ground. the Mejlik is lighter then a APC but a tad more pricey.

Wayne Galligan

140 Rx with apc 18X10PN run great