Have a brand new OS 46 fx I`m preparing to break in. Should I initially start with the needle valve settings as they are right out of the box and richen/lean from there? Seems like I heard that you should turn the high end needle valve all the way in and then back it out about 2 1/2 turns to start with, but don`t know if that`s the right thing to do or not. Thanks for any advice and Merry Christmas to all!

Andy

What do the instructions say ?

In any case, 2 1/2 turns out SEEMS about right. When you break it in remember to use the 2 and 10 rule - 2 minutes of running and let cool for 10 minutes. Do this for the first 2 or 3 tanks, gradually increasing the run time after the 1st tank. By the 4th tank you should be able to run the engine for the full tank.

I suggest using an OS #8 plug and whatever % nitro you plan on using in the engine. In "theory" the nitro content should not matter, but in the real world it seems that what ever % nitro the engine is broken in on is what it runs best on.

I have three of the Fxs and like them. I think you misread the instructions, they should read so many turns out from closed, not open. The instructions contained in the box are the best way to procede. you will find lots of instructions on how to break in a non ringed engine elsewhere in the forum and they two should be similar.

Andy, the instructions that are in the .46FX manual for break-in are wrong. Letting the engine "4-stroke" can damage the piston. I understand the instructions have been changed in the new AX manuals. If you do a search here at RCU, the proper method can be found.

Thanks for the input guys. Needless to say, I`m thoroughly confused.

DO NOT FOLLOW THE BREAK IN AS DESCRIBED IN THE MANUAL!!!

It's wrong, and has been pointed out many times on RCU.

Check the FAQ page on the OS website it's different from the manual..

I just broke mine in the wrong way and found out later...

Here's the link to the OS FAQ

http://www.osengines.com/faq/product-faq.html

No 4-cycling rich as described in the manual...

When I broke in an OS 46 AX I just ran it slightly rich for a few tanks then gradually leaned it a little with each tank after that. On the first tank I ran it 2-3 minutes at a time then let it cool completely and repeated. That was a year ago and it has probably 200+ flights on it now and it absolutely screams. It cranks easy, idles great and is one of the best 2 strokes I have ever owned.

WCB

when you are running it rich for a a few minutes, and then letting it cool.. are you doing this at full throttle, idle, or somewhere in between?

Sachin

Full throttle. Peak the engine and IMMEDIATELY back off about 3/8 turn to richen it up slightly. If you are breaking it in using the "2 & 10" method, the second 2 minute run only back it off about 1/4 turn, from then on just back it off 1/8 turn. What you want to do @ 1/8 turn is have the engine rpms drop about 300 - 400 rpms.

Dear O.S.,

My brand new FX 46 tanked.

Sincerely,
Unhappy Customer

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Dear Unhappy Customer,

Did you break in your new FX 46 according to the instructions provided with the engine?

Sincerely,
O.S.

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Dear O.S.,

No, the fellas on RCU said the instructions in the manual supplied with the engine were wrong, so I broke it in according to what they told me to do.

Sincerely,
Unhappy Customer

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Dear Unhappy Customer,

O.S. suggests that you get the fellas on RCU to buy you a new engine.

Sincerely,
O.S.

This is true.. OS has to cover any problems if you follow their
break-in be it within the box or online... But their service has
been great.. So they may even cover RCU fellas as long as
you say it the right way... The manual said to.....
I followed the manual and I've had no problems to date, I've
seen a few start it and run RICH for the whole tank than go fly
running it slightly rich for 3 more tanks than it all it'll give..
In my short 9+ months in this hobby all the FX/AX's are all
running just great so far...

I myself just got a brand new AX and i love it so far ! today was my 1st flight with it , i broke it in according to the manual ...I hate the leaking seam muffler though

Do a search and you will find that "BAX" the tower hobbies/futaba/os representative has posted more than once that the "four cycling" part of the break-in on the FX/AX non-ringed engines is WRONG!
This is the factory rep saying the factory manual is wrong! The four-cycling does not let the engine come up to proper operating temperature and causes premature piston/liner wear and a lot of extra stress on the rod.
I just recently witnessed a brand new 46AX on a new trainer started and flown rich to "break it in". The engine never did run right and the owner bad-mouthed OS engines as being no good when it was the engine tuner at fault.
FB

I broke mine in according the manual, and it runs great and has been running for a long time! So what does that prove?

As to a rep coming on RCU and saying the O.S. manual is WRONG, I wonder why O.S. didn't revise the manual. Seems like a poor business model to publish a manual with a break-in method that you know is going to ruin the engine. I bet their engines would be about $10 a piece if they didn't have to keep replacing all the ones that are broken in in accordance with the supplied manual.

As to why the manual wasn't changed- that question was asked and no suitable answer was given . Your right -the outcome on just a couple of engines doesn't prove anything. Glad your engine turned out ok. Tower replaced the engine I mentioned in the earlier post. They also replaced one of their AXi engines that was treated the same way by another new flyer and that engine ended up with an egg shaped lower end on the connecting rod. That type of service costs and guess who pays in the end?
FB