Hi,

I was given an old plane for free from a fellow club member...... its got a OS20FP 2 stroke in it, the question is it looks like the carbs gummed up as it wont move or turn at all. Also the 2 screws with attach the carb to the engine the heads have worn away soo i cant even undo them........ seems like the engine has good compression its just not been used for years.............

Is thier anything i could try to loosen this or should this just be a bin job ? lol


Thx

Fill it with marvel mystery oil and let it soak a few minutes, then start to work it slowly. It will loosen up really fast. Clean the engine good and fill it with marvel before you turn it much. Get it good and lubed up.

Those are good old engines. don't let it get away.

Very often just heating the carb will free it up. If you have a heat gun, just heat it up and try to move it while it is hot. If it moves, then use some fuel or after run oil on it to keep it free. If not take the above advice and soak it in kerosene or alcohol over night and try again.

You can even try a few drops of fuel first.

I have one of those fridge food keepers made of nylon with the snap on lid. About the size of a pound of butter. You know that last 1/2 or 1 in. of fuel that you don't use? pour it to fill to 3/4 full in the keeper and drop your engine in either together or apart. Let it soak for a couple of hrs. and use a brass wire brush on it. Wear rubber gloves and safety goggles. Nitro not nice for the eyes or skin. Will loosen tight motors and get rid of the cooked on castor oil. Keep it sealed and you can use it over and over. Really bad ones may take a couple of soakings.

Thx guys for the reply after a bit of tinkering about and fuel and oil its loose now

But lol, i undone and fiddled with a few screws.......... can anyone tell me how to adjust them back to the right settings ??????

I undone the Rotor Guide Screw and the Air Bleed Screw......... thier back in but im not too sure how to set them up.............

I got here a bit late, but I was going to say that if the engine turned enough for you to know it had good compression, and it was just the throttle barrel stuck, then just hit it with some fuel and wiggle by hand, no disassembly necessary. Though you do want to make sure the airbleed hole isn't blocked.

The proper setting for the airbleed screw will be set by running the engine and seeing if the low end is too rich or too lean. For a starting point, try having the screw cover about half the hole.

The throttle stop screw should be set so that the barrel moves freely with out binding. Personally, I always set them so that the barrel can be fully closed by the throttle servo, killing the engine. So that usually means getting it just far enough in to the carb to keep things from falling apart, but allow full, free movement.

An engine that has been stuck (even just the carb barrel) from sitting too long should be flushed out with fuel at a minimum. You want to get any accumulated dirt and debris OUT. I would pull the backplate and pour fuel in (cover carb opening with your thumb)... set the backplate in place and shake well... remove the backplate again and pour out some filthy fuel. If its really bad... repeat. Then bolt the backplate back on.

Bolt the engine back on the plane and DON'T attach the throttle control.

Too rich is always safer (for the engine) than too lean.

Close the air bleed completely then open it 1 turn (it will be too rich there)
(if it is not an air bleed carb... REMOVE the idle needle. close the main barrel, turn in the idle needle until it has slightly increased resistance or you see the throttle barrel get pushed by the needle (watch CLOSELY!) open the idle needle 3 turns)

Close the main needle completely and open it 3 turns.

As stated above... set the throttle barrel limit so it will open fully, and close down JUST completely. (maybe a small visible crack... but not much)

Now hook up the throttle control linkages. (I will assume a non-computer radio below...)

Turn on the TX and RX and verify the controls all respond correctly with no binding. Be extra sure of checking the throttle for full range. (include the trim tab in here... you want both the sitck and the tab at full for full open... both at minimum for fully closed.

Set the trim lever to full throttle and the stick to minimum. The throttle barrel should be appx 1/4 to 1/5 open.

Follow safe engine starting proceedures... (get help if you don't know them... the prop can take a big chunk out of you if you aren't careful.)

The engine should run. It may not run well or for long... but you just slowly close the main needle to make it run.

Carefully bring it to full throttle and tune the high end. You can't tune the low end until the high end is correct.

The low end should be set by slowly bringing the engine to slower and slower speed. You should be able to have it at a slow, stable idle with minimum main stick and just a bit under 1/2 trim. (carb open appx where a 1/32 square balsa stick could be inserted in the crack without scraping off any balsa) slowly open the air bleed , or close the idle needle to achieve this.