YANK AND BANK

THANK'S W8YE! HAVE YOU USED THIS THIS METHOD?

w8ye

My Feedback: (16)

I have not personally used the SWAK on a model airplane engine but have used it at work

Beej

Hi All,

Sorry for the slight change of topic. I have been trying with modest success to tune the idle on my 46 FX, and have been reading all of the advice that's out there, including reading the actual manual!. It's a "new" engine - just in storage for a number of years. I followed the instructions for screw re-set (I think I may have gone past the sweet spot by using increments that were too large). The instruction for the 46 FX (not AX) say to wind the screw out around 1.5 turns after having closed the carburetor barrel and wind the screw down to the stop position (clockwise). My question is that there reaches a point where winding the mixture screw down itself seems to open the carburetor barrel, is this normal? If so, I assume that the true "stop point" for the idle mixture screw is the point at which it begins to force open the carburetor barrel and I need to wind out around 1.5 turns from this point. Under normal circumstances (ie, 1.5 x turns out) would you normally expect that to be set slightly on the rich or lean side for smooth idle and transition (it's the upper end of the transition to high speed where I am getting the hesitation)?

Any help, much appreciated.

best

Beej

w8ye

My Feedback: (16)

Most of your assumptions are correct

Ultimately, the Low speed mixture needs to be slightly rich to facilitate acceleration when you give it the throttle. Therefore it does not work so well to do the pinch test on the idle circuit.

Set the idle mixture by having it as lean as possible and still being able to accelerate

jzrf6c

I have been flying the new 46AX for several years. I NEVER adjusted the low speed on the first one. However, after about three years(two years past the warrenty) the coating came off the cylinder sleeve! The way I discovered this was I could not get it to idle. I believe the firts batch of AX engines used the "OLD" sleeves from the FX batch that were know to be bad.

I don't see how it would be possible for the carb barel to open when you screw in the idle adjustment. There is no physical connection. If you screw in the adjustmet too far you should just hit the idel barrel and may damage it.

w8ye

My Feedback: (16)

OS went to the new plating process after the introduction of the "AX".

The locating pin for the "FX" is in the rear and the one for the "AX" is above the exhaust port

Beej

Thank you Everybody, and now for possibly the dumbest question ever on this forum........

OS 46 FX manual talks about adjusting the "mixture control screw" to set idle transition etc, but the exploded view of the engine does not show a "mixture control screw" anywhere (referred to on page 15, 23 and others..) , but a "throttle stop screw" (page 34, carburetor 40b exploded view). It's the throttle stop screw I have been "adjusting". Don't all laugh at once but am I on the wrong track here?

Thanks!

Beej

Beej

It's OK (slaps hand on forehead..), I've worked out what a thicko I have been - mixture control needle runs inside the spraybar and when I get home and peer into the middle of the throttle arm I bet I will find a small screw in there.

cheers,

Beej

w8ye

My Feedback: (16)

This is not the first time

Thisstrangeengine

My O.S engines:
.25 FSR on an r/c combat wing
.49 Wankel rotary stored in original box
.32 F-ABC x2 currently in a scratch built twin
.48 4 stroke in a scratch built mid-wing aerobatic plane
.70 4 stroke in an 18 year old Goldberg Cub
.120 4 stroke w/pump/version 1 in a 1/4 scale Lanier Laser 200
.240 FF Pegasus 4 Cylinder 4 stroke (NIB)
I Love my O.S. engines...

Broken Wings

My Feedback: (20)

Anyone still running the OS 108 FSR or BX-1? I bought a used one that's in real good condition.

Any Long Term use up dates?

rcdude7

My Feedback: (264)

I have a 1.08 and a .91fsr, they are as rugged as the day is long. Most of these engines are probably still in service, too bad OS shut down the parts pipeline, I guess they had to do it to get us to buy the new AX engines.

I doubt OS will ever build another engine as tough as the fsr, a engine that lasts this long has got to be bad for repeat business.....................

Kostas1

Is there a dramatic difference in power between the x2 of them ?

Kostas1

I am proud to post that i am AGAIN a happy O.S. owner..

O.S. 108FSR

Broken Wings

My Feedback: (20)

I bought a used one,(1.08) I like it very much.

gtlavin56

Any one that comment about this, I ran my OS 91 FX with 14X6 prop to get 11 krpm +, instead of 16x8 that I was using before (8 krpm). Now I heard a metal knock, too metalic, at the beginning was somekinf less lowder and less frquent, at the end I decided to land after 3 or 4 mins of flying to chech id muffler or something was loose. Nothing all in the right place.

Have you heard something simiar in your engines? colud be some called "Knocking" due to the fuel?? Thanks in advise for uour comments and advise.

NM2K

My Feedback: (14)

Our glow two-stroke engines will suffer from preignition if the timing is too far advanced.

So how do we advance the timing too far? Well, we could burn too much nitro for the available cooling air and size of the prop. Or we could run too hot of a glow plug to begin with. But all of these things are all pointing to one way of advancing the timing and that is by overheating the engine.

Some fellows think that if they tuned their engine with a 14x6 prop, then they can leave the mixture needles the same when they switch to a 16x8 prop. Sorry, it doesn't work that way. I'm just tossing this in for those that are unaware, not the OP (original poster). The needles not only need to be reset (usually just the high speed needle) when you change a prop, but it doesn't hurt to check it a couple of times during an entire flying day, assuming that you adjusted it during the first run of the day.


Ed Cregger

maukaonyx

Proud owner of many OS engines. Once I got into them after a K&B .40 and Royal .40 eons ago, I never turned back. Lately I have tried a few Saitos and like them too, just not quite as much as OS. Here's my OS stuff:

.25 FP in a Modeltech Thunderbird (old ARC)
.46 LA used to be in a Tower Trainer 40 till a mid air took her down. Awaiting a proper home after replacing the broken carb.
.52 Surpass in Funstar 40
.70 Surpass II in GP Shoestring
.70 Surpass II in GP Extra 300SP
.70 Surpass II in Thunder Tiger Imagine 50
.91 Surpass II w/pump in Modeltech P-47 Jug
.91 Surpass II in TWM Intruder 90R awaiting maiden
1.20 Surpass SE in CG Ultimate built in 92
1.20 Surpass III w/pump in NitroModels 69" Yak 54
1.60 FX in CMP Giles 202
On deck are a.70 Surpass, .91 Surpass, and 1.60FX. YES I kinda love OS engines. To me they all perform flawlessly. I only had one OS that I hated, make that 2...the cheap .70 four stroke and the .70 Ultimate (blue top). Those were nothing but trouble. Jon

mistermnkim

My Feedback: (153)

Love my os engines as well! I have a few 40LA s that i have had forever a 46LA , a 46AX in a elder, a FT-160 gemini twin in my 1/4 scale cub and a FF-320 Pegasus quad for my 1/3 scale Tri pacer.

rambler53

My Feedback: (494)

.25 FX, fantastic little engine. Never flew a bad one. .40 - .45 FSR, on a pipe, 16.5 k rpm 9X6 prop, fun combination on scat cat planes. Nice to see something keep up with the HP Gold Cup engines similar in weight and same mount size.
Owned and flew dozens of .46 FX and AX engines, no complaints.

AX 55 and AX 75, way over-rated and didn't like them. Picky on prop size, ugly as a radiator. Dumped my AX 120 thinking it would be another disappointment. Went back to Super Tigre when AX became ridiculously over-priced.

SF 46 - (4D carb) SF / RF .61 (7L carb) versions were my favorite until I replaced them all with Rossi.

1.08 FSR seemed a little bit heavy for my taste. I replaced it with a Webra 1.20 and it was just as reliable and stronger, but that's another thread.
Saito 4 strokes are always my first choice.

LA and FP, not into airbleed and bushing engines with tiny carbs. Great for disposable trainer level auguring.

kochj

Version II marine engines


a metal plate added to the exhuast?? . and a cooling change on the head?

I would think a internal change would be better??? Like crankshaft and liner!>...

Looks like the inboard shares the same radical cyl. work of the 21 onroad engine....
Shood rev. really well!...

I think OS should make some gasoline boat engines....and go big with those....
Would be nice...

rcdude7

My Feedback: (264)

That thing on the exhaust is a spacer to give the muffler more volume for better power I suppose.

The head is aircooled.

The power rating is the same as the watercooled engine.

The price went up $75 over the old engine.

Uncas

My Feedback: (1)

I have an OS .46 AX running with an E-3030 muffler that was for a .46 LA. Does anyone know if that would be a problem at all as far as power output. I know it works...

JONES4110

Has anyone run the new  OS fs95V engine which has apparently replaced my favorite FS 91 surpass.  They are now obsoleted at Tower.  Just ordered the new 95V on their two day sale at a net cost of 249 with club 50 off code.
Hoping that I will like this new Saito lookalike.  Any experience on this engine would be appreciated.

spaceworm

If the .46LA muffler has an internal baffle in it, I would take it out, as I have done with my .46FX and .46AX engine mufflers.