High idle, Lsn too lean??

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Hojaz

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Hey

So i just broke in my Buggy (inferno neo 3, KE21sp) and I'm having some issues..
During break in when the motor got more loose it started to revv higher and higher, so i adjusted the idle screw a little and it got better. The original idle gap was 0,5mm.
But later on it was picking up idle again so i turned the idle screw out a little more.
Also, when i was driving and giving it 2-3/4 throttle and then released it stalls right away, but not all the time.
When the tank runs empty it doesent revv up, it just stalls immediately without any warning.
When i was done for the day i removed the airfilter and i noticed that i had no idle gap at all, maybe 0,1mm at the most. Could barely see it with my eyes.
How come it idles good anyway?
The car runs great otherwise on high speed runs, with a nice blue trail of smoke. Its on the rich side on Hsn and havent touched the Lsn at all.
The temps were around 210f and up too 250f on high speed runs.
Anyone know what it could be? Lsn set too lean from factory?

/Hojaz
 

johnnydmd

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It sounds lean to me. Idle gap should be .5 - 1mm. I've never seen an idle gap change, unless it's completely backed out and the servo is setting it.

Disconnect the linkage, and set the idle gap to 1mm. Then set the LSN to flush with the housing. Then reconnect the linkage, and make sure it's not opening the carb when at idle. Start from that point.
 

gandalfnz

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It sounds lean to me. Idle gap should be .5 - 1mm. I've never seen an idle gap change, unless it's completely backed out and the servo is setting it.

Disconnect the linkage, and set the idle gap to 1mm. Then set the LSN to flush with the housing. Then reconnect the linkage, and make sure it's not opening the carb when at idle. Start from that point.
What Johnny said

With engine not running, take off the air filter, pay attention to idle gap, now keep applying full brake and then letting throttle go back to neutral
When you do this, does the idle gap change even a tiny bit?

You car stalls when you let go off the throttle because your idle gap is too small or non existent.

Set it back to 0.5, and adjust the idle with LSN.
What I do is keep richening the LSN until I notice that take off is sluggish is car shuts off completely, I then start leaning LSN until take off is nice and crisp.
Thats it.

I find that at least on Traxxas Engines, LSN is always set a bit lean, so that engine temps are not too low when doing the break in.
 
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Hojaz

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It sounds lean to me. Idle gap should be .5 - 1mm. I've never seen an idle gap change, unless it's completely backed out and the servo is setting it.

Disconnect the linkage, and set the idle gap to 1mm. Then set the LSN to flush with the housing. Then reconnect the linkage, and make sure it's not opening the carb when at idle. Start from that point.
The idle gap didnt change by itself, since the idle was getting higher and higher for every run i adjusted the idle screw out to get it back to normal and i guess i did it too much since there was no gap left when i looked. But it still had a good idle, how can that be? Could a lean Lsn make a good idle with almost no idle gap?

What Johnny said

With engine not running, take off the air filter, pay attention to idle gap, now keep applying full brake and then letting throttle go back to neutral
When you do this, does the idle gap change even a tiny bit?

You car stalls when you let go off the throttle because your idle gap is too small or non existent.

Set it back to 0.5, and adjust the idle with LSN.
What I do is keep richening the LSN until I notice that take off is sluggish is car shuts off completely, I then start leaning LSN until take off is nice and crisp.
Thats it.

I find that at least on Traxxas Engines, LSN is always set a bit lean, so that engine temps are not too low when doing the break in.
I dont think it changes, atleast it didnt when i looked at it before i started the break in.

Oh okey, didnt know that they set it a bit lean for break in, but that explains some things.

I got like a "preparation" paper that came with the car, it says to make sure all needles are Flush with the housing, but yesterday when i was looking through the big manual i found factory settings for the engine, wich i missed before.
It says that Lsn should be 0,5mm OUT from Flush (mine is set at flush from factory) and that the Hsn should be 3,5 turns from fully tightened.
If i set my hsn to flush it would be like close to 5 turns i think.. so i dont know why the papers say different things. 5 turns out would be reeeally rich i guess, cause mine was spitting allot of fuel with the 3,5 turns.

I will give it a try by setting the idle with lsn, didnt wanna mess around too much with it before i know how it works lol. Thanks.
 

gandalfnz

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The idle gap didnt change by itself, since the idle was getting higher and higher for every run i adjusted the idle screw out to get it back to normal and i guess i did it too much since there was no gap left when i looked. But it still had a good idle, how can that be? Could a lean Lsn make a good idle with almost no idle gap?


I dont think it changes, atleast it didnt when i looked at it before i started the break in.

Oh okey, didnt know that they set it a bit lean for break in, but that explains some things.

I got like a "preparation" paper that came with the car, it says to make sure all needles are Flush with the housing, but yesterday when i was looking through the big manual i found factory settings for the engine, wich i missed before.
It says that Lsn should be 0,5mm OUT from Flush (mine is set at flush from factory) and that the Hsn should be 3,5 turns from fully tightened.
If i set my hsn to flush it would be like close to 5 turns i think.. so i dont know why the papers say different things. 5 turns out would be reeeally rich i guess, cause mine was spitting allot of fuel with the 3,5 turns.

I will give it a try by setting the idle with lsn, didnt wanna mess around too much with it before i know how it works lol. Thanks.
Make sure you set the idle gap back to 0.5 mm , then adjust the idle with LSN.
 

johnnydmd

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It says that Lsn should be 0,5mm OUT from Flush (mine is set at flush from factory) and that the Hsn should be 3,5 turns from fully tightened.

I looked at my KE25 last night. I think those are the correct settings. My LSN is about .05 out from flush, and my HSN is in a bit from flush. Not sure, but it's probably the same carb. Getting specs for those engines doesn't appear easy.
 

alfredwong2003

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I don't usually follow nothing much, usually just open about 3 turns from close for HSN, then it should be 1/2 a turn either way for most engines to get it running, then tune from there. It also depending on temperature and atmospheric pressure, it will usually a 1/4 turn from after you tune it. The key is make sure you get fuel in and no air leaks.
 

Hojaz

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I looked at my KE25 last night. I think those are the correct settings. My LSN is about .05 out from flush, and my HSN is in a bit from flush. Not sure, but it's probably the same carb. Getting specs for those engines doesn't appear easy.
No it doesn't, and with the manual that says different settings its not making it any easier lol.
I'm guessing my problem is the lsn then, since yours is out from flush also. I'm gonna give it a go tomorrow if i have the time and richen the lsn up a tad.
If the lsn has been to lean during break in, could that have damaged the engine or the break in procedure in some way??
 

Hojaz

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Problem solved, the lsn was way too lean..
Idle gap set back to about 0,5 and then adjusted the idle with lsn like you guys said. But i had to richen it allot to get it to seattle down.
No wonder i had to pull the starter til' my hand was bleeding lol, now it starts right away on the first pull and it doesn't stall when letting go of throttle, idles a little higher after high speed pass and then goes down to a smooth idle after 1-2 sec or so.
It also feels allot better when hitting the throttle from a stand still.

Thanks guys!
 

gandalfnz

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Problem solved, the lsn was way too lean..
Idle gap set back to about 0,5 and then adjusted the idle with lsn like you guys said. But i had to richen it allot to get it to seattle down.
No wonder i had to pull the starter til' my hand was bleeding lol, now it starts right away on the first pull and it doesn't stall when letting go of throttle, idles a little higher after high speed pass and then goes down to a smooth idle after 1-2 sec or so.
It also feels allot better when hitting the throttle from a stand still.

Thanks guys!
Glad it worked!
 
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