new .91 C-spec?

[Jimmyy2kws6]

I've always used a YS91ST4 in my Fury's and I am thinking about trying the new OS C-spec. http://www.osengines.com/engines/osmg1982.html Does it run good out of the box or should I expect to mod it?

Jimmy

[R-4-L]

as it is, you'd need to mod it, (so I keep hearing), some ppl have problems (most ppl) when the engine leans at hover range, OS released a needle to be attached to the RETURN valve to control how much return is allowed thus adjusting the mid-range setting is made possible..

http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXHRB7

OS part number: 29081910

note all this is applies for the 60M carb that comes with the c-spec PS version.

[DavidH]

Jimmy,
The motor will run good of the box if some precautions are taken.
First when you get the motor and put it in the heli and go to start it the first time.
Hook all the fuel tubing to everything like it needs to be.
Fill the tank with fuel.
Now take the fuel line loose from the carb on the engine. Just let this line lay out to the side. Now take your starter and turn the engine over like your trying to start it. Keep the starter turning till a stream of fuel is coming out of the line that has been disconnected from the carb. Let this stream of fuel run for 10-15 seconds while you still turning the engine with the starter.
Now you can connect the fuel line to the carb and start the engine.

The reason for doing the above is to get any debries that might be in the pump out of it. That is the reason there is problems with the PS motor sometimes. Debries will be in the pump from the manufactuering process and get in the carb when they engine is started. Then the needle valves will not set correctly.

Just a suggestion that will help you have success with the PS motor.

David

[sumonzu]

Jimmy,
I have this engine, it is a great one, and I suggest you to buy the third needle anyway. It helps a lot while fine tuning the engine. Note that you will have the full power from it only when completely broke in; so it's better to run a little on the rich side for some gallons.

Marcello

[Jimmyy2kws6]

Thanks for the help. I couldn't reply earlier due to Hurricane Wilma knocking down my ISP :roll:

Jimmy

[flyinbill1]

I have a relatively new OS .91 CSpec engine with pump and ran the engine straight out of the box. I have probably 6 tanks of fuel through the engine at a rich setting;about 1.5 turns out. I have only hovered the Freya; no forward flight. The engine isn't getting hot and there is plenty of smoke.

I didn't know that for a new engine one needed to flush the pump before starting the engine. So my question is, do I need to remove the needle valve assembly and clean it to assure there is no debris, or is it too late?

By the way, my engine is stock; no third needle.

Bill Harden

[DavidH]

Bill,
With 6 tanks already thru the engine. If there had been any trash in the pump you would have already known it. The reason I suggest flushing the pump, there is usually debri in the pump from the manufactuering process. You can still flush it, but it will be useless at this point.

You will most likely find out you will need the third needle when you start doing more than hovering the model. When you begin transistioning back and forth between the high end and mid range on the carb. You will then see why the third needle is needed. From my experience you will be chasing the mixture trying to get the high end mixture and mid range mixture to run correctly. Without the third needle it is hard to get it exactly right.

David