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Nitro tune help

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Tunpa

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While waiting for my baja to arrive, I decided to try and get this crappy truck running, I am running 20% nitro, it has a sh-21 engine, now the problem is that when I let it idle for 10 second and try to take of, it either stalls or revs high and then take of, is that the low speed needle or idle? Thanks guys
 
Remove the air filter and look down the throat of the carb. The idle gap should be about 1mm or the thickness of a credit card. Once that is set, I'd give the lsn about 1/8th of a turn richer. Adjust itfrom there.

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The idle gap is 1mm, it still idles around 30-40 seconds then dies, it sounds like the idle is high when started and then it gradually drops till it dies, if I keep my finger on the throttle for 3+ seconds at about 20% throttle after the idle drops, it stays still and then gradually gets its power and moves of, any help would be helpfull as I want to give this away working
 
The idle gap is 1mm, it still idles around 30-40 seconds then dies, it sounds like the idle is high when started and then it gradually drops till it dies, if I keep my finger on the throttle for 3+ seconds at about 20% throttle after the idle drops, it stays still and then gradually gets its power and moves of, any help would be helpfull as I want to give this away working

I think you need to do 2 things;
1) turn UP your fast idle adjustment - yes UP
2) turn your low speed mixture OUT 1/2 turn to richen the low speed mixture.

#1 will increase the idle speed and #2 will reduce the idle speed. I think you are too lean but as the engine sits and idles it slowly goes from lean to rich and the idle speed drops.

Also, if you are having tuning problems I suggest that you use a HOT glow plug so that the engine will keep running when rich. This will make the engine tuning process less frustrating.

Good luck,

Lee
 
Check your slipper clutch if its to loose as well, if it rev up a lot before it start moving I would tighten it up a bit.

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I think you need to do 2 things;
1) turn UP your fast idle adjustment - yes UP
2) turn your low speed mixture OUT 1/2 turn to richen the low speed mixture.

#1 will increase the idle speed and #2 will reduce the idle speed. I think you are too lean but as the engine sits and idles it slowly goes from lean to rich and the idle speed drops.

Also, if you are having tuning problems I suggest that you use a HOT glow plug so that the engine will keep running when rich. This will make the engine tuning process less frustrating.

Good luck,

Lee

Thank you! It was on the rich side with lsn, the truck is great now, thanks alot!
 
Thank you! It was on the rich side with lsn, the truck is great now, thanks alot!

Tuning an engine without being able to hear it is very difficult. The sound of the engine is usually a big clue into which way the mixture adjustments need to be turned.

A lean engine usually has a sharp irritating bark to it and a rich engine has a muted sound (I can't find the right words to describe it).

Glad I could help!

Lee
 
whats the starting point?
how many turns on each needle?

Try starting your own thread and include the type of engine and some pictures of your setup if possible and everyone here will be more than happy to help you out.
 
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