Hi everyone,.....no i don't wana break-into anyones house.....i wana break-in my new OS .46AX engine.....the manual goes on to say that i should run it only once on ground changing needle settings every 10 seconds from 2 and 4 cycle settings.....then start flying on rich setting for a few flights without any stress runs. Not too sure about this.....i used to think that it should be run a 3-4 tanks on the ground on a rich setting.

So thats what i did.....run 4 tanks of 10% fuel though it on a rich setting with a 10*7 prop.....had some trouble differentiating between 2 and 4 cycle sounds (newbie) .....so i run it at about 2 turns open needle.....lots of smoke and oil came out of the exaust.

Does this mean the engine is broken in.....is there some way of knowing that the engine is broken in .....do i need to do something more .....have i damaged the engine by not following the Manual .....seriously i can't differentiate between 2 and 4 cycle sound. Dying to get it in the air....plz help

Thanks in advance
Ken

Running it rich wont hurt it as much as running lean. Lean means excess heat, and in a tight new engine, which is already generating extra heat as the parts wear in, that can lead to damage. I have the same 2-4 stroke sound problem (newbie too). I opened it up until it ran rough, aka loping, sorta like a little harley engine. I then ran the 10 second sequence mentioned in the manual. I was told by my lhs owner that for the 46 ax, thats all it should take. I have, just to be safe ran abit rich for the first gallon of fuel. But when I dialed it in to "flight mix" It ran like a striped ape.

what about the throtle.....do u open it fully or 1/2 or 1/3 or idle or somethin else.....i did 2 tanks on fast idle and the next 2 on full throtle....rich settings on all ofcourse.

Please, please, please...Use the search function (little box located in the left upper corner)
There are tons of break-in techniques posted here!

Two tips though:
1. Yes, break in a full throttle and control the engine by the high speed needle
2. Too lean mean too hot/damage, too rich mean too cold/not hot enough to break in/excessive wear.

Not rocket science and nothing to be afraiid of, these new ABC/ABN engines require very little break-in and are hard to kill.

Ken,

I have done quite a few of these engines and they are pretty solid.

I have always done exactly what the book tells you to do.

The way to tell between 2 and 4 stroke sound is this. Before starting, turn the needle valve clockwise until it seats but do not force it, then open the needle valve turning it counter-clockwise about 3 full turns and start the engine. Once it starts wait about 30 seconds for it to warm up and take it to full throttle. At this point the engine will be spitting fuel and making allot of smoke and if you listen closely it also sounds as if it is missing which it actually is because it is only firing on every other stroke (4-cycle operation) and it most likely will be vibrating allot, now start closing the needle valve until the engine starts to pick up rpm's which will be about 1 to 1 1/2 turns and when you hear the sound change to a high pitch scream and the rpm's increase allot, that's when it's running in 2-cycle operation. All of the above is based on adjusting the high speed needle valve.

If you cannot tell the difference in sound then a tach will help allot.

After running 4 tanks through it, doing the above will not help that much as long as you did it with it spiting lots of fuel from the exhaust you should be OK.

Once you have the breakin completed, refuel the plane, close the needle valve and reopen it to about 1 1/2 turns and start the engine, now lean it but turning the needle clockwise and listen closely and you will hear the rpm's increase, once they stop increasing stop leaning the needle and turn it counter-clockwise about 1/4 turn, you are looking to get max rpm by leaning it then you richen it to loose approx. 300 to 500 rpm beacuse when you fly it will lean out on it's own in the air. Now go fly. After about 4 flights you will needle to readjust the high speed once more and start working on the low speed needle.

The low speed needle on these engines is for setting the mixture from idle to mid-throttle and has everything to do with the transition from low speed to high speed and how quickly and smoothly that happens.

The low speed needle is a very small screw inside the hole where the throttle connection is on the right side of the carb (looking from the cockpit forward) and never ever try to adjust it with the engine running.

To adjust the low speed first make sure the high speed is set as described above (max rpm minus 300 - 500 rpm, this must be done first), then start the engine and blip the throttle quickly from idle to half throttle. If the engine stumbles (hesitates) and spits fuel and smoke then picks up rpm then the low speed is too rich. (The low speed needle is somewhat sensitive), you need to turn the screw clockwise (lean) only 1/8 of a turn. Now if the engine stumbles and hesitates and picks up rpms quickly then dies without spitting fuel and smoke you will need to turn the low speed counter-clockwise to richen it again only turning it 1/8 turn. Once you adjust the low speed retest it to make sure.

Once you have finished the low speed then verify that going from idle to high speed quickly is working good. Once you move the throttle from idle to full throttle quickly, the engine should immediately go to full throttle without stumbling, hesitating or it dying. Do this also to half throttle to verify the low speed.

You should be able to do all of the needle settings as described above in less than one tank of fuel. Keep at it as that is a great engine and you will love it. I recommend an 11X5 or 11X6 or an 11X7 prop for that engine as long as the plane has the ground clearance for it.

OS normally sets the low speed a little rich at the factory so it will usually take about a 1/4 total turn lean to get it to run and transition well.

I do the half throttle thing to confirm the results to full throttle as the low speed needle handles the mixture from idle to half throttle then at which point the high speed needle takes over.

enjoy

Thanks Bill for such gr8 detail....i'm sure to benifit from it now and in future....
Test005 i'm new and a lil carefull with everythin i do with this lil beauty tht cost me so much..... personalised advice works much better, for me atleast....... plus there are so many Guru's of this art in this group.... so i guess i'll just keep askin.....thanks for the too rich too cold info. though.....never thought bout tht.

I know what you mean turnmelose and I understand that you're nervouse and want to get it exactly right.
What I'm saying here is that if you do a search on break-in you get more than 300 hits.
Let's say that 50% of those are for two strokes and 50% are for fourstrokes.
The OS 46-ax is a poular engine that many people own and the break in will be just like any other ABC/ABN two-stroke whether it's magnum, Thunder Tiger, Super Tigre, Irvine etc...
There are litterarly hundreds of anwers to this brea-in question and if you read up on them you'd make yourself a much better own opinion than a single "personal" answer would provide.

My point here is that every time I logon to the beginners forum there are post after post with the same questions.
People might get tired of answering the exact same questions all the time because nobody even bothers to make a search prior to jumping the gun and posting their question.

If all newcomers took some time browsing the beginners forum, make a few searches and read up they'd learn much more than a specific question will provide.
There are tons of information here to be found about beginner equipment, training, clubs, building techniques etc...

If nobody bothers to make a search or read some of the questions already asked, the forum might as well reset every night and start over on a clean sheet each morning.