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Nitro Car Dies when on idle - need help

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Old 10-15-2012, 04:39 AM
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garyedwards
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Default Nitro Car Dies when on idle - need help

Car works fine for 2 minutes, untill after i hit full throttle when rpm's are decreasing and idles for a second and then shuts off. Seems to be a good amount of blue smoke trailing from exhaust pipe, so i think its either something to do with the low end needle being to lean even thou its flush with the outside or the middle needle(idle needle). I would appreciate if you could give me your thought on a solution Cheers!
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Old 10-15-2012, 08:46 AM
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Default RE: Nitro Car Dies when on idle - need help

sounds liike your idle gap is too small. or you clutch may have gone bad.
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Old 10-15-2012, 07:34 PM
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Default RE: Nitro Car Dies when on idle - need help

how much should i open it?
its pretty much already 1mm
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Old 10-15-2012, 08:17 PM
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Default RE: Nitro Car Dies when on idle - need help

if the idle gap is already at 1mm then that is most likely not your problem. it sounds more like the tune is off. it sounds like the car was probably tuned while the engine was still cold. where are the needles set at in relation to the factory stock settings? when tuning a nitro engine it is best to tune when the engine is up to it's running temperature. also what kind of car are you running and what engine is in it?

If you are seeing lots of blue smoke while running the engine is probably too rich and at idle is unable to supply enough air to keep the engine running. Try leaning out the HSN one hour at a time to see if there is any improvement. If the engine is still at factory settings it will probably need to be lean out a little for best performance. Just don't lean it out too much or you can destroy your engine.


One more thing: if you are new to tuning nitro engines, go to YouTube and search for "nitro engine tuning" HPI Racing has some excellent videos showing how to tune properly.
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Old 10-15-2012, 08:30 PM
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Default RE: Nitro Car Dies when on idle - need help

its a hobao gpx4 with a hyper .12 engine. Factory settings for high speed needle 2.5 turns outwards, which is very sluggish, so its way below factory setting so its less than 2 turns with the high speed needle with still a good amount of smoke trailing the exhaust pipe. the low speed needle is about flush with outside ring it sits in and the idle screw make the slide card show only 1mm of the carb?
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Old 10-18-2012, 08:09 PM
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Default RE: Nitro Car Dies when on idle - need help

Quote:
ORIGINAL: garyedwards

its a hobao gpx4 with a hyper .12 engine. Factory settings for high speed needle 2.5 turns outwards, which is very sluggish, so its way below factory setting so its less than 2 turns with the high speed needle with still a good amount of smoke trailing the exhaust pipe. the low speed needle is about flush with outside ring it sits in and the idle screw make the slide card show only 1mm of the carb?
Does the idle gap remain at 1mm while you hit the brakes?
Always set the gap with the screw on the carb and not with radio trims.

EDIT- Again, always set your tune on a fully warmed engine.


To get it tuned, First get the engine fully warmed up!
Never tune a cold engine.
Start from factory settings on all needles. (Maybe 1/8 to 1/4 in on the HSN from factory if already broken in.)

Be sure to set the idle gap as well as needles to factory settings before retuning from scratch.


Get your HSN set first.
Keep leaning the HSN 1/8 turn in at a time and watch the performance increase.
Making a couple top speed passes each time to let the engine get used to the new setting.
When you see a decrease in performance turn the HSN back out 1/8 to 1/4 turn to richen it back into the safe zone. Keep an eye on temps as well.
Good top speed and good trail of smoke at all speeds is what you want.

Then set the LSN.
You can do the pinch or punch test, or both.

PUNCH TEST-
Once you have the HSN set, engine warmed up.
Make a couple top speed passes and bring it in and let idle for 10- 15 seconds.
Then give it 3/4 to full throttle.
If is slow to take off and smokes alot you are too rich and need to start leaning the LSN.
If it takes off fast, rev's and dies, etc... it is too lean and you need to richen the LSN.

If it smokes and is slow taking off, start turning the LSN in 1/12 to 1/8 turn and again make a few passes to get it used to the new setting in between adjustments.

PINCH TEST-
Make a couple top speed passes, bring it in and pinch off the fuel line near the carb.
Start counting 1...2...3...
It should run for about 3 seconds before it revs and dies.
If it runs longer you need to lean the LSN.
If less than 3 seconds you need to richen the LSN.


Once you have good acceleration and still have smoke at all speeds you are done.
You may need to reset the idle on the carb once you are done tuning.

Weather always plays into your tuning and you will need to adjust the HSN for day to day conditions.
I.E.- colder weather requires more rich settings and vice versa.

I am just a basher and no expert so use this info at your own risk!

SLAYER
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Old 02-08-2015, 03:02 AM
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HI i have a question my nitro engine is running at high throttle or high speed but when it returns back to low speed or idle its stalls even my idle gap is 1 mm or i think 1.5 mm so is it related to low speed needle ????


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Old 02-08-2015, 07:45 AM
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Quote:
Originally Posted by Ala Sarchel View Post
HI i have a question my nitro engine is running at high throttle or high speed but when it returns back to low speed or idle its stalls even my idle gap is 1 mm or i think 1.5 mm so is it related to low speed needle ????


Can you be more specific,alot of things plays a role on how the engine runs.
Like how old the car is.
Had it sit for along time?
Had it been tune after break-in?
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Old 02-08-2015, 10:03 AM
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It's old engine as i said when I go to full throttle but it return back to idle stalls even the idle gap is 1 mm
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Old 02-08-2015, 10:37 AM
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Quote:
Originally Posted by Ala Sarchel View Post
It's old engine as i said when I go to full throttle but it return back to idle stalls even the idle gap is 1 mm
Does the engine rev up an die,or just dies?

It may not be the tune,it could be an air leak in the tank or fuel line.Or not enough pressure built up in the tank when
you throttle down.
I would check those areas before I blame the carb first,An make sure the tank filter & tank is clean,an dont have
airleaks around the cap.
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Old 02-10-2015, 06:25 AM
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Quote:
Originally Posted by Ala Sarchel View Post
HI i have a question my nitro engine is running at high throttle or high speed but when it returns back to low speed or idle its stalls even my idle gap is 1 mm or i think 1.5 mm so is it related to low speed needle ????
Although I do not agree with all of the information I do think you should read the post before yours again...

Quote:
Originally Posted by SLAYERDUDE View Post
Does the idle gap remain at 1mm while you hit the brakes?
Always set the gap with the screw on the carb and not with radio trims.

EDIT- Again, always set your tune on a fully warmed engine.


To get it tuned, First get the engine fully warmed up!
Never tune a cold engine.
Start from factory settings on all needles. (Maybe 1/8 to 1/4 in on the HSN from factory if already broken in.)

Be sure to set the idle gap as well as needles to factory settings before retuning from scratch.


Get your HSN set first.
Keep leaning the HSN 1/8 turn in at a time and watch the performance increase.
Making a couple top speed passes each time to let the engine get used to the new setting.
When you see a decrease in performance turn the HSN back out 1/8 to 1/4 turn to richen it back into the safe zone. Keep an eye on temps as well.
Good top speed and good trail of smoke at all speeds is what you want.

Then set the LSN.
You can do the pinch or punch test, or both.

PUNCH TEST-
Once you have the HSN set, engine warmed up.
Make a couple top speed passes and bring it in and let idle for 10- 15 seconds.
Then give it 3/4 to full throttle.
If is slow to take off and smokes alot you are too rich and need to start leaning the LSN.
If it takes off fast, rev's and dies, etc... it is too lean and you need to richen the LSN.

If it smokes and is slow taking off, start turning the LSN in 1/12 to 1/8 turn and again make a few passes to get it used to the new setting in between adjustments.

PINCH TEST-
Make a couple top speed passes, bring it in and pinch off the fuel line near the carb.
Start counting 1...2...3...
It should run for about 3 seconds before it revs and dies.
If it runs longer you need to lean the LSN.
If less than 3 seconds you need to richen the LSN.


Once you have good acceleration and still have smoke at all speeds you are done.
You may need to reset the idle on the carb once you are done tuning.

Weather always plays into your tuning and you will need to adjust the HSN for day to day conditions.
I.E.- colder weather requires more rich settings and vice versa.

I am just a basher and no expert so use this info at your own risk!

SLAYER
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