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Old 01-19-2010, 12:46 AM   #16
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I would go the other way around. I believe the lsn is set on the rich site.
Lean the lsn a bit and drop the idle a little

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Old 01-19-2010, 08:14 AM   #17
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Quote:
Originally Posted by wingracer View Post
2. The idle is set too high. With it at that high idle, back off the idle screw until it comes down to a normal idle. It will probably want to stall then because the LSN is way too rich now. Lean the LSN until it idles right again.
Exactly what I thought.
A too rich LSN masked by a wide idle.
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Old 01-19-2010, 08:36 AM   #18
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Originally Posted by triplesix View Post
Exactly what I thought.
A too rich LSN masked by a wide idle.
Yeah, it's hard to tell without being there to look at it and hear it but when he said the idle gap is around 2mm, that's way too much.
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Old 01-20-2010, 04:12 AM   #19
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Ill try leaning it out more and see what happens..

The idle does drop back to normal after a few seconds.

the idle gap is way less than 2mm.. i can hardly see through it or stick a pin in it.
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Old 01-25-2010, 08:07 PM   #20
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Any updates?
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Old 01-26-2010, 01:30 PM   #21
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Just read over this post, and he stated that it was an old Nova SX engine, so looking through my data base found the standard factory needle settings for that carb.

Novarossi .12 (Base Carburetor Settings)
Low Speed: 3.25 turns out
High Speed: 4..50 turns out
Mid-Range: Flush with the carb body
Idle: adjust the idle needle screw, so that the engine reaches a regular RPM
(usually 0.5 to 1mm slide piston open).

Also found some basic carb FAQ's that maybe useful

What is the "Top End" needle?
The "Top End" needle is the large needle valve that adjust how much fuel is delivered to the engine from half throttle to full throttle.

What is the "Bottom End or Low end" needle?
This needle adjusts how much fuel the motor gets at idle and at the first crack of the throttle.

What does is mean when people say my motor is "too rich?"
This means that there is too much fuel being supplies and not all of it is being burned off in the combustion cycle.

What does it mean when people say my motor is "too lean?"
This means that the motor is not getting enough fuel. This can make a motor difficult to start or make it run too hot.

How do I know if my motor is "too lean?"
A motor that is too "lean" will not stay running. Usually will flame out at full throttle or not idle. Temperature is one way to check this. Another way is to examine the plug. The element in the plug will turn close to "white" and be dry if the motor is too lean. This condition is very damaging to the motor since the motor relies on fuel for it's oil supply as well.

How do I know if my motor is "too rich?"
A motor that is too "rich" will spit raw fuel out of the exhaust pipe and never really reach top RPM or "clear out" meaning to not burn all the fuel. This motor will usually idle OK but will bog and die the second the throttle is applied if the low end is "rich" or never reach full RPM is the "top end" is rich.

What does it mean when people say I have to adjust the "bottom end?"
This means you need to adjust the low-speed setting on the carburetor.

How do I adjust the idle?
The idle is adjusted by turning the idle screw on the carburetor. This can be found by looking at the manual that came with the motor. Turning the screw in will increase the idle speed and turning the screw out will decrease the idle speed. These screws are simply a stop for the slide or barrel of the carburetor.

Why does my car die after only idling for a few seconds?
This usually means the low-speed needle (i.e. bottom end) is too lean. Try turning the low speed needle out (counter clockwise) about 1/8 of a turn at a time until the car will idle.

Why does my car die right after I accelerate from a stop?
This again is usually a lean condition on the "bottom end." Try "richening" up the low-speed needle by turning it out 1/8 of a turn at a time until this condition stops.

How far should I turn the needle valve when I make adjustments.
Any needle valve should only be adjusted in 1/8 turn increments. These are very sensitive adjustments.

Are there "starting" points for my needle valve settings?
Always follow the manufacture's recommendations.

How would I know if I have an air leak in my carburetor?
This is a tough one. An air leak will make the motor very very difficult to tune. Usually the idle will be inconsistent and the motor will generally not want to perform consistently. This is a difficult condition to detect.

When I rev my car it seems to idle at a higher RPM for a few seconds then settle down. Why?
This could be from an small air leak in the carb, or from a motor that is running a bit too lean on LSN.

What type of oil should I use on my foam air filter?
We suggest any "tacky" petroleum based oil. Motorcycle shops sell this for ATV's and dirt bikes air cleaners. Don not use silicone based oils. K&N air filter oil is specifically made for K&N filters and is not good for use on foam filters.

Adjusting needle settings - before putting the car on the track

First you have to warm up the engine for a couple of minutes with a very light acceleration.

Adjusting of the idle speed: When the engine is at about 85 - 100 C, keep the carburetor at the minimum rpm (with the throttle completely closed) and adjust the idle needle screw (air needle) so that the engine reaches a regular RPM (.5 to 1mm slide piston open).Once the engine is idling and has come up to operating temperature proceed as follows:

Stage 1: Setting the main needle just a little rich

Take the car off the ground, and open the throttle fully. The engine should run cleanly until it reaches 80% of top RPM, after which it should start to run slightly rich (4-stroking):

If the engine runs cleanly all the way up to top RPM, richen the main needle (counter-clockwise) until it starts to 4-stroke at approximately 80% of its top RPM
If the engine runs too rich (4-stroking all the way) lean the main needle (clockwise) until it only starts to 4-stroke at approximately 80% of its top RPM

Stage 2: Re-setting the idle speed

Take the car off the ground, and open the throttle fully for 2-3 seconds. Close the carburetor and check the idle speed that occurs immediately after.

If the engine stops almost immediately, turn the idle adjustment screw clockwise to increase the idle RPM.
If the idle RPM is too high, turn the idle adjustment screw counter-clockwise to reduce the idle RPM.

Stage 3: Setting the low speed needle

Open the carburetor for 2-3 seconds and let the engine clean out. Close the carburetor and let the engine idle.

If the engine idles for 2-5 seconds and then the idle RPM decreases, the engine is running too rich during idle. Lean the low speed needle (clockwise) to remedy this condition. Repeat this step until the engine idles reliably at a constant RPM for at least 20-30 seconds after the carburetor has been opened for 2-3 seconds.
If the engine idles for 2-5 seconds and then the idle RPM increases, the engine is running too lean during idle. Richen the low speed needle (counter-clockwise) to remedy this situation.
If the engine will not idle at all, richen the low speed needle (counter-clockwise), or turn the idle adjustment screw clockwise to increase the idle RPM.

NOTE: Because adjusting the low speed needle affects the idle RPM, use the idle adjustment screw to get the engine to idle at the right RPM.

Once you are satisfied that you have achieved reliable carburetor settings, you are ready to put you car on the track.

Adjusting needle settings at the track

You can only fine-tune the main needle setting at the track. Initially, the main needle should still be set a little rich. Fill the fuel tank, run the car up to maximum speed for a few laps, and check if it reaches top RPM without running rich towards the end (4-stroking). Lean the main needle by small increments (1/12 of a turn, like 1 hour on a clock) and run the car again. Repeat these small adjustments until the engine accelerates well and reaches maximum speed without running rich. It is advised to then richen the main needle 1/8 of a turn (counter-clockwise).

Running the engine too lean will cause the engine to overheat, resulting in excessive engine wear and possibly breakdown. A fast, simple way to check the engine temperature is to apply a few drops of water to the cylinder head. The drops should evaporate only after 3-5 seconds. If they evaporate immediately the engine is too hot; richen the main needle 1/8 of a turn (counter-clockwise). Check engine temperature regularly and often.

The idle RPM and low speed needle settings may require a little fine tuning after the main needle has been set properly (see stages 2 and 3). Once properly adjusted, the engine should produce a strong, high-pitched sound at maximum speed, and a thin trail of smoke should be visible from the exhaust tailpipe.
On the track adjust the rear low speed needle, using only a turn both ways.

NOTE: The carburetor settings may change with changes in weather conditions, fuel, glow plug or exhaust system. After changing any of these, always richen the main needle (counter-clockwise) to a turn and then re-adjust the main needle again on the track.

Hope this Helps
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Old 01-30-2010, 11:37 PM   #22
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Originally Posted by rmdhawaii View Post
Any updates?
your right, was too rich.

i figured out when i was putting the LSN back to flush, it the needle wasent going in all the way, so when i turned it 3.5 turns out, it was actually about 5.5t out, so iscrewed it in all the way and put it back on 3.5t

I took it on the track and ran awesome... noticed when i let off the throttle on the straight it was making that lean rev up noise though.. so it might need to richen the LSN a lil.

Last edited by LiL_JaSoN; 01-30-2010 at 11:51 PM.
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Old 02-09-2010, 01:12 AM   #23
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wat do u recommend if the mid range needle be if the engine has one?

set it flush?
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Old 02-09-2010, 02:21 AM   #24
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Quote:
Originally Posted by LiL_JaSoN View Post
wat do u recommend if the mid range needle be if the engine has one?

set it flush?
usually left it untouched...flush.
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Old 02-09-2010, 04:13 AM   #25
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Well one idea is if you have access to a camera. tape it and post a you tube link the next time you have a problem lol
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Old 02-12-2010, 01:59 AM   #26
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Quote:
Originally Posted by rx7ttlm View Post
Well one idea is if you have access to a camera. tape it and post a you tube link the next time you have a problem lol
+1
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