stuart macrory Posted January 12, 2009 Share Posted January 12, 2009 hi,just bought an asp 120 fs and the instructions are the worst ive seen for a 4 stroke newbie like me.i can see the high speed needle but is the low speed needle the one that has a spring on the screw beside the fuel inlet nipple also there is a slot head grub screw in the centre of the throttle arm(what is this for??)also when you push the throttle arm to the fully closed position there is still an opening in the carb of about 4mmand 1 last one what is ment by twin needle on this engineplease help as i really want to get this engine goingmany thanks Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 12, 2009 Share Posted January 12, 2009 1) The little screw with the spring on is a throttle stop screw - virtually redundant really with TX servo travel EPA etc. 2) The "grub screw" in the centre line of the throttle barrel arm is the one you need for low end adjustment3) The small gap in the barrel when throttle arm is closed is because item 1 is screwed in too far. 4) twin needle because it has err, twin needles - one high speed and the one in item 2 Quote Link to comment Share on other sites More sharing options...
stuart macrory Posted January 12, 2009 Author Share Posted January 12, 2009 many thanks timboso the twin needle thing really applys to most if not all engines thenits just when i bought the engine it sort of promoted the fact that it was twin needle as if it was something special Quote Link to comment Share on other sites More sharing options...
stuart macrory Posted January 12, 2009 Author Share Posted January 12, 2009 i dont suppose you know the factory settings for the 2 needles Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 12, 2009 Share Posted January 12, 2009 Some use an air bleed screw rather than a fuel flow needle to control the idle mixture - most though now use 2 needles... no big deal really. ASP and SC engines ( both identical actually ) are jolly fine cheapy copies of the "Other Sort " IYSWIM Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 12, 2009 Share Posted January 12, 2009 I would leave the idle alone - it it coughs and splutters and hesitates on pick up its probably rich, so turn it in a tad. My SCs always seemed happiest at about 1.25 - 1.5 turns out on the main - best to set em slightly rich IMO Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted January 13, 2009 Share Posted January 13, 2009 My 2 stroke SC needed some slow needle adjustment after it was run in, so I would run a few tanks throughit and see how it goes.As with anything else, do small adjustments and only one adjustment at a time.If the needle is wound in too far and the mixture gets too weak, the engine will spit and splutter and over hear. As Timbo says, err on the rich side. Quote Link to comment Share on other sites More sharing options...
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