O.S. 40FS Running

[John Sheehy]

I've just bought a second hand Super 60 with an OS 40FS engine.  I've only flown with 2 strokes till now and would appreciate any help or advice on running a FS.  One problem I've come across already is the controls.  There is the usual needle setting on one side, but on the other side is a push pull control which is a mystery to me. Any ideas?  Also , what is the purpose of the breather nipple on the crankcase and why is it connected to the fuel tank?

Thanks

John

[Tim Mackey]

dont recognize the push pull control, unless it is a choke ? The crank breather on many Four strokers these days vent back to the intake manifold so that any expunged ( luvverrly word that aint it ) oil, fumes, etc do not splash out all over the atmosphere. I dont think it should be plumbed into the tank. Tank pressure ( if required ) is normally from the exhaust nipple.

[John Sheehy]

Thanks Timbo,

On checking the parts list I found it is a choke.  I can't see where on the inlet manifold (unifold?) the tube could go.

[Tim Mackey]

Then just let it vent to air.

[Engine Doctor]

Hi John . The breather on the OS 40 just vents to air the pipe should only be a couple of inches long to shoot waste oil out of the cowl. The only adjust ments on the FS carb are the main needle and an air bleed idle mixture screw . The FS is nice runnig engine and very economical and quiet.

E.D

[John Silvester]

Yes John, I agree with engine doctor. I'm sure that you will have used your engine by now - I find that a 6oz tank is good for 20 minutes plus, so don't use one too large.I use Laser  4 stroke mix for all my engines - ie. no nitro.You may lose a little flexibility but still have plenty of power.A Graupner 11x6 prop works well on my Veron Tomtit 52" span Biplane.Keep oiled with after-run (through the breather pipe -- half a teaspoon or so)  before you put it to bed ! Keep away from 2 stroke castor oil mixes and you won't get gummed up. IMHO, one of O.S's finest engines.

  J.S.

[Martin Harris - Moderator]

The breather is actually very important.  Apart from venting the crankcase pressure, it ensures that oil mist is pulled through the camshaft area to lubricate the valve gear.  Try to use the recommended length of pipe - too long and it won't pull the mist through properly leading to excessive camshaft /follower wear.

[John Silvester]

Hi Martin. I have  previously heard the caution about too long a breather pipe and can see the reasoning.Some O/S engines have breather nipples at the rear, some at the front, being piped to the intake manifold (later marks) and now with the Alpha series, all oil is led where needed,  internally. This seems to be an elegant solution. Those of us with earlier engines should go with your ( and makers) advice , but I'm still wondering how to keep the Laser from blowing oil everywhere. Any proven ideas would be very wecome!

[Former Member]

[This posting has been removed]

[Harry Maclean]

If you have to have a longer vent just put a Y pipe (the sort used in fish tanks and come in various sizes) with the two connections upper most in the line  one connected the other free to atmosphere, about an inch from the engine( these can be bought from most garden centres, fit enough pipe to clear the engine. The reason for using this is the free end of the pipe allows air in to to stop a vaccum? forming. Then push enough ppipe on the other end to clear the fus.

[Colin Scovell]

Hi fella`s, I have just read your comments on the OS40FS, I am very interested as I am thinking

of getting one for an upcoming project..

I have a` POWER PLANES INTERNATIONAL' CUSTOM CRUISER, unstarted kitbelieved to be from about 1988? I think it might suit it well if I can find someone who has an OS40FS.

Does anyone know what happened to the company Power Planes International? Their phone no.

was in Wales but there is no answer!

[Binky]

Hi guy i have two OS40FS engines, one since 1986, which i acquired secondhand! Superb little engines easy to operate and service/repair.