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Old 04-10-2009, 08:19 PM   #1
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Default Idle question...

OK, so my wifes revo is idling weird now.... What happened is I had to have the idle set really high to get it to maintain an idle, and I think I might have figured out why.....

I was tuning the HSN first (from factory settings on HS and LS needles), then I'd leave the idle high and tune the LSN..... I remember now that I should be lowering the idle before tuning the low speed Needle.... But the issue I was having tonight was that the idle speed screw was working in reverse... The car would be idling good, but high, so I would unscrew (counterclockwise) the idle speed screw to lessen the gap, and the idle would start rising (like it's getting lean).

MY QUESTION:

If I had the lsn set to idle good at about 3 times the gap in the slide that it should be at, and then tried lowering the idle via the idle speed screw, does it lean out the engine? I hope so, cuz that would solve my problem.... I can't check till morning, so I was hoping someone in here might have run into this issue before...

Thanx!!!
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Old 04-10-2009, 08:31 PM   #2
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Sounds like your lsn is too lean. Richen it and try again. You can test your lsn by squezzing the fule tubing about an inch from the carb. Your engine should increase rpm slightly and then dies at about 3-5 seconds.
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Old 04-10-2009, 08:34 PM   #3
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Originally Posted by rgrassey@me.com View Post
Sounds like your lsn is too lean. Richen it and try again. You can test your lsn by squezzing the fule tubing about an inch from the carb. Your engine should increase rpm slightly and then dies at about 3-5 seconds.
The problem is I can't lower the idle to where it needs to be, so I'm setting the LSN to idle good at way too high of rpms... When I do the pinch test at that high of an idle, it works perfect, but when I try to lower the idle after that, I unscrew the idle screw slowly and the idle actually raises... that's my issue

I just checked and my LSN is supposed to be flush as a starting point and it's screwed in I'd say a whole turn or more... In the AM I'm gonna set it back to flush and try lowering my idle then...
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Old 04-10-2009, 08:52 PM   #4
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ya i think its lean
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Old 04-10-2009, 08:58 PM   #5
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Originally Posted by rgrassey@me.com View Post
ya i think its lean
I don't think I explained my question very well, so here goes again:

Does turning your idle down lean the mixture? Does turning down the idle restrict fuel flow via the lsn faster than it restricts the air via the slide closing... Reason I say that is because at a 2.5mm gap idle, it's fueling properly and using the pinch test it's perfect, but when I go to lessen the gap it sounds like I'm leaning the truck out because the idle actually raises....

Does that make sense?
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Old 04-10-2009, 09:31 PM   #6
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No changing the idle screw does not lean your mixture its just making it seem lean because your lsn was already lean. By having your idles so high it was masking the fact that your lsn was so lean.
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Old 04-10-2009, 09:33 PM   #7
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Double check the idle gap with the filter OFF....Ive seen it FAR too many time's where guys have the Idle Jacked to compensate for the highspeed/lowspeed being out of wack and it causes All sorts of issues with tuning.
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Old 04-11-2009, 04:37 AM   #8
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Set the idle where should be first, then run it to get some heat in it, then HSN for temps, then LS. Don't even try to get it close untill it's warmed up, or you'll chase tune all day. If this don't work, start looking for air leaks. BTW, tuning on the 'net is tough to do, but we'll keep pecking at it.
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