Engine Idling
 

When my engine idles it spits out raw fuel. Is my low speed needle too rich or is this supposed to happen?:confused:

Its probly not all raw fuel but the oil that is in the fuel. But yes, that means it is very rich.

How do i know that i leaned it out enough?

It should be idling higher.

Do a few speed passes to clear it out and then let come to idle. Idle should sit fairly high for a few seconds and then drop off (even then it is most likely a tad rich). However it shouldnt sit high enough to engage the clutch.

Search youtube for 2 stage idle, it will give you an idea of what to look/listen for.

Too lean and it will idle way too high and either stall or bog really bad when you hit the throttle. There is also a rich bog. usually happens with a lower idle.

There is a lot of stuff covered at the top of the forum in the stickies. Some engines tune a bit differently but the basics are usually about the same.

I would start with a good idle air gap. This is where a lot of confusion starts.

There is always a time for "get-to-know" a new engine. When I started with nitro, it took me 2 engines and couple of glow plugs to learn the art. Finding the right needle setting is challenging and as well frustrating at times.

In my case, I also experience the same during the first few minutes from cold start but gradually disappears as my engine warms up.

I thought that if you did a speed pass to clean it out that if it was too rich then it would high idle for a few seconds then drop, but for a properly tuned engine it should not change idles after you clean it out. This is in the Jarod Tebo video as well as in the engine tuning guide in this forum. Most people seem to have the HSN too lean and the LSN too rich which shortens the life of the engine because on the high end it is too lean but people don't notice because of the extra fuel in the crankcase from a rich LSN.

You want your idle to drop to a nice purr without loading up. Typically you don't want a 2nd stage idle this will happen when your engine is new from its pinch. As you stated watch the Tebo video its a good description

Check your idle gap first. That is how far your carb is open when your throttle is at neutral. Should be 0.5mm to 1.0mm. I use a thin paper clip as a feeler gauge.

If that is good, then your idle is controlled by the LSN. Get it up to temp and let it idle. Once it idles good, do a high speed pass to clean it out and bring it back in. It should go directly to a stable idle.

If it's good, I let it idle for about 10-15 seconds then punch it. There should be no hesitation or bogging on take off and good smoke. If there is no smoke, you are too lean. If there is bogging, it is still too rich. Adjust as necessary. You may have to adjust the idle screw A LITTLE to get your idle where you want it once you move the LSN .

The videos mentioned by the previous posters are a very good tool.

i've been having this issue as well. very frustrating. i have my HSN extremely lean, and the hottest i get is 170F, im scared to turn any more in case its too lean.. but the truck runs awesome, so just keep leaning, keep an eye on temp.

i read 200F is a good running temp. does anyone know if its bad for the engine to run low temps?

How small of incriments should I turn my LSN? Im fairly good at tuning the HSN but the LSN im kind of hesistant about it since i dont want to lean it out too much and cause the temps to soar.

im no expert but i think it's 1 hour incriments. think of the screw as a clock and turn 1 hour at a time and take it for a drive

i don't mean to hi jack your thread but it might be better to ask here since were on the subject. (if this takes away from the TS question just ignore this post)

im running rich, when i try to lean the hsn my idle goes up pretty high to the point it worries me, my idle gap is soo tiny now, way less then .5mm. if i try to lean anymore my idle goes up and my gap is at the point if it closes anymore it stalls. i dont even know how to ask this question, it seems so easy but when i start tuning i end up getting screwed up and randomly turning stuff. i follow the right instructions but i get different results then i should. i think it maybe because im 16ft above sea level and do not know the correct settings to start with.

anyways, is the right order: (assuming settings are default)

-start car
-tune HSN (should i leave idle to last no matter how high the idle gets?)
-how do i know the HSN is correct? without touch the other settings?
-after HSN is set, do a pinch test, if pinch test is ok, leave the LSN
-after above, then adjust idle?

Is your engine already broke in? Your LSN is probably too lean. Whenever you lean the HSN, you are also effecting the LSN! So when you touch HSN, you may have to retune the LSN.

If your engine is already broke in (and your HSN is in the ballpark), then I would:
-Richen up both needles just enough that you are on the rich side
-Set idle gap
-Tune LSN until it's near ideal idle, bottom end is clearing out okay, and it drops back to idle smoothly - you may have to retune idle during this
-Hit track and get the engine back up to full temps with HSN on rich side still
-Tune HSN, run some more - lean it until the engine is hitting full RPM's and 'clearing out' without hesitation (listen carefully; going beyond this just leans the engine and brings up temps - there's no need to run overly lean for regular club racing); I also use smoke as an indicator, but different fuels have different oils/percentages, so if you tune with smoke, know your fuel!
-Bring back into pits after driving some laps and verify LSN/idle doesn't need touched again - this is where I'd also do the 10-15 second test on LSN
-I temp throughout the process just to confirm what I'm hearing/seeing/doing

thanks man, great info! i will try it tomorrow and give you an update. i'll try to get a quick video up as well, i kinda suck at explaining things lol

yes the engine is broken in. i was having trouble getting them running at first, and ran out of patience quickly, and worried i would break something, the site i ordered them from told me they would break in and tune both for free (i bought a truck and drift car at the same time)

i got them back expecting to un box and rip around, i couldnt even get them started. it turns out they were broken in and tuned at 3600 ft above sea level (texas maybe?), and i am 16 ft above sea level in Nova Scotia. i actually got them working pretty to my liking (the pros would laugh at me tho i think), but it's the very "fine" tuning thats killing me.

any idea what the starting points are at sea level? my HSN is just about 5 turns out and still running rich, fuel from pipe, smoke, hottest i seen was 170, usually by the time i stop and grab the gun its at 150

+1. Exactly. Idle gap, LSN then HSN. Once HSN is good, verify LSN setting & idle. Then rip on it!!!

Always tune to performance and smoke, not temperature. Only use temperature as a check to make sure you aren't burning it up. There is no "magic number" for temperature. Anything north of 280-300 is bad, unless you really enjoy buying engines.