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Old 01-20-2009, 12:37 PM   #1
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Default High Idle after WOT

I have CEN Genesis GST 7.7 running a Corsa .46 motor with a 20% fuel mix. After I hit WOT the engine still screams! I've checked the carb and it does return to idle but it still acts like it's on WOT! What gives? Also, I tried setting the LSN a little richer and the engine eventually calms down after WOT (takes about 15-20 sec) but then after about 2 min the engine dies!! Also, if I try leaning out the HSN the engines runs fill e but after about 7-10 min of Sunni g the enigine looses power and no longer goes Fast even at WOT! I need help!?!?!
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Old 01-20-2009, 12:45 PM   #2
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It sounds like the the engine is too lean to me. Take and fatting the master needle and see what it does.
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Old 01-20-2009, 12:46 PM   #3
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sounds like HSN too lean and LSN to rich. When it looses power is it overheating, whats the temps?
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Old 01-20-2009, 01:35 PM   #4
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Check your idle gap. Could be to big causing you to lean the LSN to compensate.
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Old 01-20-2009, 01:50 PM   #5
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Originally Posted by slaytanic View Post
Check your idle gap. Could be to big causing you to lean the LSN to compensate.
I almost agree. Idle speed (gap) is set to high and the LSN is set too "rich" to compensate.

A linkage binding or servo problem can cause a simialar problem so be sure it's not a mechanical problem before you start turning needles
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Old 01-20-2009, 05:23 PM   #6
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It sounds too lean, but I would check to see if the servo is not causing the issue, I had one that would not return to neutral and it would not show up till running the truggy for a few minutes and secondly I would check the carb? is it a slide, if so check to see if it is moving smoothly and not binding, I again had one that would bind up after warming up and then go away after it cooled down, that is very frustrating
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Old 01-20-2009, 06:35 PM   #7
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Originally Posted by Gliptal View Post
sounds like HSN too lean and LSN to rich. When it looses power is it overheating, whats the temps?
+1 and idle set to high to compensate for the rich LSN.

whats happening is when you do a WOT run then stop, the engine over revs as you have cleared out the build up of fuel due to the rich bottom end, as the bottom loads up again you idle drops back to normal.

check your Idle gap is between .7 and 1mm get you engine up to temp richen your top end by about 1/2 a turn lean your bottom end so that the buggy takes off with out bogging then fine tune from there.
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Old 01-20-2009, 08:10 PM   #8
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Originally Posted by John Schafer View Post
I almost agree. Idle speed (gap) is set to high and the LSN is set too "rich" to compensate.

A linkage binding or servo problem can cause a simialar problem so be sure it's not a mechanical problem before you start turning needles
True. My idle gap does seem a little wide but... A 1mm gap I'd soooooo small. I look at a ruler and my gap is about 1cm. How big is 1mm?? Barely open at all? Then if I lower the gap... I also have to lean out the LSN... Correct?
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Old 01-20-2009, 08:12 PM   #9
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Originally Posted by Gliptal View Post
sounds like HSN too lean and LSN to rich. When it looses power is it overheating, whats the temps?
Yes the engine dies overheat. Hot enough the sizzle a drop of water like a frying pan sizzles fried eggs...

Any suggestions?
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Old 01-20-2009, 08:13 PM   #10
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waaaaayyyyyy too lean on the top
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Old 01-20-2009, 08:15 PM   #11
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Originally Posted by ChicoRCKing View Post
I look at a ruler and my gap is about 1cm. How big is 1mm??

lol 1cm? thats 10mm
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Old 01-20-2009, 08:48 PM   #12
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I would set the needles back to factory settings. Check the idle gap. Make sure that it is no more than 1mm when neutral. Once your idle gap is set retune your mill for performance. If you are still having problems you might have a leak somewhere.
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Old 01-20-2009, 10:11 PM   #13
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Quote:
Originally Posted by ChicoRCKing View Post
True. My idle gap does seem a little wide but... A 1mm gap I'd soooooo small. I look at a ruler and my gap is about 1cm. How big is 1mm?? Barely open at all? Then if I lower the gap... I also have to lean out the LSN... Correct?
That's correct.
As Tree said, it would be a good idea to reset the carb to factory/beak-in settings and re-tune from there.
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