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120SP idle question

Old 09-28-2009, 11:00 PM
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Default 120SP idle question

I have just purchased a 120SP. Got it running on the bench with 1.5 gallons of Omega10. Engine is running ok at mid and high with little vibration. But, I am having trouble with the idle. At less that 2000 it wants to die. Dumb question but the instructions talk about adjusting the idle needle but where is it? Is it under the carb and is it the small flat head screw? Also, the instructions talk about the "secondary needle" under running in instuctions what is that? DO I need to break in more before I get good idle?
Old 09-29-2009, 11:59 AM
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Default RE: 120SP idle question

yes, the idle adjust screw is in the throttle barrel. I had the same problem at idle, let it warm up a bit so every thing is at operating temp then let it idle and do your adjustments with the engine warmed up. the more fuel you put through it the better.
Old 10-01-2009, 06:36 PM
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Default RE: 120SP idle question

Hey Mistral,

I guess there aren't many people watching this forum these days.

Give this a try. It might work for you. Start your engine up as you normally do and let it warm up for about a minute or so. After it is warm, take it to full throttle and adjust to max rpm with the main needle screw. Once you've found max rpm, richen it with 3 or 4 counterclockwise clicks of the main needle and throttle back slowly and see how low it will idle.

I'm guessing you are either running too rich or too lean. If after you've done this, it will not idle at around 1500 rpm, you may need to tweak the idle screw. If you do it, only move it 1/8 turn max at a time. It's pretty sensitive. RCV says that the idle screw is usually pretty close to correct from the factory. You will probably need to shut it off to make these idle screw adjustments.

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