fx777

I have a 120 AX, whch is my 8th os engine. I broke it in with a 16 8 APC prop with no problems, except for excessive vibration at an idle. I changed out to a 15 6 Evolution Prop, which at first had a very smooth idle, but after a tank of 5% Omega, same fuel used with break in, it now either cuts out when it reaches top rpm; or it sustains top rpm (10,050) but stalls out, when I cut back to an idle. I also noticed there is some in and out freeplay movement in the crank when the prop is removed. I checked the tank and all hose connections. Could the smaller prop have damaged the engine?

djohnson

I just received a OS Gemini 240 in the box from a friend who is getting to old to continue and he knew I have always wanted one of these motors.

What airplane would be a good chioceabout how heavy will this pull and still be aerobatic? Best prop 18x10 or 18x12? I fly IMAC and jets but love all kinds of RC.

w8ye

My Feedback: (16)

The power to weight ratio of the 240 doesn't usually lend itself to 3D type aerobatics. They are most typically used on Piper J-3 Cub type planes

jerryjohnson

OS 56 ATX. This engine is new, 6 or 8 flights and I have trouble with the stock muffler coming loose. I have tried thread lock, but it seems to give way to the heat. Any suggestions of what to use on the muffler bolt threads?

Bax

My Feedback: (11)

Do you mean the O.S. Max .55 AX or the O.S. FS-a56? O.S. doesn't have a ".56 ATX" engine.

jerryjohnson

My mistake, it is a 55 AX

Speedy-Gonzales

My Feedback: (202)

Looking desperately for a Piston and sleeve assembly for the O.S. 61 VF Rear Exhaust. Would appreciate any leads. Speedy

rainedave

My Feedback: (1)

This has to be one of the loudest OS's in my stable, and I have a few with exhaust baffles and no mufflers.

Purchased for $9.99 as seen in the first photo.

After cleaning, replacing gaskets and installing the nifty exhaust/throttle gadget I put it on the stand and ran it up. It didn't pull fuel from the tank too well, so I had to prime it through the venturi. Once I got the NV set it would start easily with the chicken stick. I used Powermaster GMA 5% nitro/29% all castor fuel and an old Top Flite 9x4. Like I said, it's loud at full throttle! But, it has a high "Cool factor."

David

NM2K

My Feedback: (14)

The difference between before and after is astounding. I think that cleaning engines in antifreeze can be addictive. I love the magical transformation that takes place, as in your situation.

Just think of all of the engines that have been neglected because they look bad, but which have lots of useful life left.


Ed Cregger

rainedave

My Feedback: (1)

Thanks Ed. I used Dawn Power Dissolver and Copper Cream on this one (no antifreeze).

The internals were like new. I doubt it was run more than a tank or two.

Like you say, there must be tons of old engines that are filthy on the outside and pristine inside. Think of all the people who bought engines in the '60s and '70s and could never get them started (no one to help them), so they just gave up, tossing the engines in a box. I think this engine was probably one of those. The red spray paint makes me think that maybe a kid got this engine as a gift, put it in a plane, spray painted it, but never even got it running, or flew it once, crashed it and moved on to another hobby.

There's a real sense of reward saving these old relics and giving them new life.

David

griesel

I have the following OS engines: ( I have deliberately left out the "max" )
91 FX ( both old and new remote needle )
H80R/C both pre and post 1973 versions
H60R/C EARLY VERSION W/CARB IN REAR
H60F GP ( gold head ) ( I have a 2nd one that is more like a copper head? )
H60F GR (black head)
60FP
55 AX
H40R/C
LA40
Wankel ( version 1, earliest)
20R/C
19R/C
10R/C
I probably missed a few.
I also have manuals for most of these.
What I have found out is that at least the larger engines
are as light or lighter than their modern counterparts.
where the plane is supposed to use an AX 46 I can use a H60F GR
with only a 0.4 ounce penalty. ( or none if I use a 60's muffler).
where a plane is supposed to use a 61 FX I can substitute
an H80R/C. This can swing a 16 inch prop, but the engine seems
to really like 14X6.
I have an H60F GR on a Hobbico SuperStar and can easily take
off with 40% throttle and cruise with about 30%. fun fun fun.
I have only 8 flights on her but I got about 6 ounces of fuel
15%/18% for 16 minutes of mostly slow cruising with more throttle
for some aerobatics.
I have finally ended up with 15%/18% with some castor used on the 60's and 80's with no ill effect so far.
The H60F GR is rated for 10% to 30% nitro with 23% castor.
I am using OS#8 glo plugs instead of #7 or #9.
The dual plug 80's are very insensitive to adjustment and
seem to run with almost any old setting. Also they seem to run very reliably.
It is kind of fun to say I am using a 30 to 40 year old engines; complete with
strap on mufflers.

RC Specialties

Bax,

I have a question you may be able to answer. What is the exhaust thread size on the OS FS120? It appears the newer models have a 14x.75 thread. Some of the older engines have a different thread. Can you clarify the differences and when it changed?

Jim

lcball20

I just recently bought a OS 65 La engine and I can't get the thing to idle. I turn the mixture to full lean and then back out two full turns as suggested by manual. The engine runs up fine, but when I bring the engine to idle it idles for a second then actually builds rpms for a few seconds and then dies. Any Help.

d_bodary

My Feedback: (85)

sounds like the idle maybe to lean. Try screwing the airbleed screw in two turns and then trying it. if it doesn't work then back it out four turns.

lcball20

Thanks. I'll give that a try and see what happens.

Jetdesign

My Feedback: (8)

I've been in the hobby for not quite a year yet, and have bought 4 AX engines. I am absolutely amazed at the reliability, simplicity, fantastic service, etc.

I get the best feeling when I get to the field, prime my engine with like two prop flips, and the engine starts on the first flip with the stick.

The other day I had to change something around in my plane. I set the needles back to the starting point as suggested in the manual, and in half of (an external) 6oz fuel tank, I had the high end set, the low end set, and was having perfect transition on my 120AX. The engine barely has a gallon and a half of fuel through it, total, and runs like a dream.[8D]

I talk to them like they are my pets.[sm=bananahead.gif]

Too bad they don't make a 1.50 four stroke[&o] But then there's YS[sm=punching.gif]

w1nd6urfa

My Feedback: (4)

Jerry,
I also own the 55 AX with a Pitts muffler and didn;t have any problem with it coming loose. However on my .56 FS-a I had this issue (more vibration on 4 strokes?) until I used high-temp silicone glue - also called gasket glue, usually red color.
Muffler never came loose after 4 months flying, and also this stuff comes off easily if you need to unscrew the muffler.
I guess this is as close to perfect fit-fot-purpose as can be

Pic is .91 FS II - p

Kostas1

Hi guys!

Next week i will receive my OS 10FSR & i'm really excited because it will be the smallest and cutest engine i've ever had!

I will post some good pics after i receive it!

Kostas
Greece

jzrf6c

I've just picked up an older OS 91surpass does anyone have a hard copy or an electronic copy of the manual? Or, do you know where I can get one.

TimC

jzrf6c, I found this post by w8ye:
"The earlier Surpass I version with the silver valve cover, you will have to call customer service at Tower and they will send you a Zerox copy"
(Of the manual)

w8ye

My Feedback: (16)

New pumped four strokes

http://www.os-engines.co.jp/english/090527/pump.html

Tower does not have them listed yet

Kostas1

Guys i've added to my list an OS 10FSR..... GOD it's a jewel!


Konstantinos
Athens/Greece

w8ye

My Feedback: (16)

Fine looking little engine

dstrong2000

I pick up anOS 60FSR engine about a month ago,but on the crankcase it's says 60SR does anyone know where i can get the maunal for it if i need parts for it.
I also found the muffler that goes with this engine OS #744 muffler does anyone knows where i can get the gasket for it or can i run this engine with out the muffler gasket or can i make it. i am looking for the screws to hold the muffler in place as well.

Any help i can get will greatly apprecate thanks.
VERY NEW TO THIS HOBBY !!!!

griesel

Permatex ultra copper for most gaskets. Cover the mating surfaces with a thin layer; tighten the bolts; and wipe off
the excess with isoprophyl alcohol. osengines.com is the source for most OS questions. Some parts are available,
many are not. Almost any part shows up eventually on Ebay. Hopefully someone out there will send you a copy of
the manual. All I have H60-FGP and -FGR which are older and different. OS has some copies of older engine
manuals - see their web site.