Low throttle settings

[Geoff Bradley]

I've run in my SC42 engine but am unsure about the throttle setting at idle ! Can anyone help - how far open should the throttle be when looking inside the carb. I've been aiming for around 1mm of the orifice showing but have not been able to get a steady tick over without eventual engine cut out.

Any advice would be greatly appreciated.

[simon barr]

Hello Geoff,

Don't worry too much about how big or small the hole looks, just set the idle to an appropriate speed using either the trim or end point setting.

As for the motor cutting out at idle, it may be too rich at the bottom end which will flood it, so you may need to close the idle needle just a tiny bit.

Hope this helps,

Simon. 

[Tim Mackey]

I agree, but if you insist...then I suggest about as much clearance as would allow a pin to pass through

[Former Member]

[This posting has been removed]

[Hamish]

Are you giving the needle?

[arko66]

Ive had the same problem. I havent touched the idle needle as previous advice says that its factory set and I shouldnt touch it. I keep turning a click on the main needle eithrer way and she still wont potter on without a big splutter then nothing. Should I or shouldnt I, touch the idle needle?

[Myron Beaumont]

Geoff

Is it run in yet ?   Makes one hell of a difference don't you know ! Get that main  needle setting slightly rich first,( 200 ish rpm lower than max.) leaving the idle as "factory" set Then sort the idle out by VERY small adjustments ie 1/8 of a turn at a time  If you've lost the idle setting -use the blow/audible technique referred to on other threads (which I can never find )    PS can you help me with this digital stuff ?

[Myron Beaumont]

PS  Sorry Just re-read your initial ques]tion   You said it is run in   OK   For how long ? A litre of fuel or what?

[batcho99]

Like Myron said, small adjustments on the idle mixture screw, then see how she sounds. Or just bin it and get a 4 banger

[Myron Beaumont]

batcho99        That's a bit drastic  !  Next you'll be recommending a 'lectric motor  

[Geoff Bradley]

I think I'll stick to my 2 ticker thanks

Myron - I've used just under a litre of fuel - would you consider that sufficient or does it vary greatly depending on manufacturing tolerances ? I was told that about 3 tanks  was sufficient for run in.

[batcho99]

Ok Geoff  The engine should be run in sufficient enough to start leaning out a couple of clicks after about 4 tanks. Normally you wouldn't need to touch the idle screw from factory settings, but I have found that SC engines do take a little more time to get adjusted correctly, I've got a 32 in a fun fly (1 of 3 two strokes in my collection) and a 52 4c.  But once you've got it, it'll purr beautifully and tick over very slowly with good throttle response.