Idle Screw again....

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J-Revo

J-Revo

Well-Known Member
Messages
378
Location
Hamar, Norway
Could someone screw their idle screw all the way in and count the turns for me?
I'm still messing a bit with the jet tuning on my WT-990 carb, but I can't find a spot that I trust with the H and L jet as the idle screw was all the way in when I recived the engine. If you can give me your settings for the idle screw I have a starting point to adjust the H and L needle.

My engine is a 30.5 Zenoah but I guess this make no difference

Thanks :):)
 
When starting out new I turn it in until you just see the butterfly move, then screw it in 3 full turns. This will allow me to run rich.
Remember, as you lean out your engine you will also need to lower the idle screw. At 3 turns out you should be able to start the motor at stock settings.

Good luck and let us know how it goes.
 
Thank you so much BTB :)

I think that one of the problems is that I can't find a point where the L jet don't perform well, close to stock settings. Idle screw ALL the way inn and L jet set to 1 1/4 it works perfect. L jet at 1 turn and idle screw a bit more out it still works perfect. Now I got it at H:1 1/2 L:1 and idle screw according, and has lot of low end power.
I will now try to tune it around 3 turns out on the idle scew and L:1 1/4 H:1 1/8 as a starting point :)
 
Tried it once more now, and to keep it idling at 1 turn out on the L jet, I need to set the idle screw to 1 1/4 out from bottom. Starting it and keep it idle at stoch settings I must almost all the way in with the idle screw. This really starts to bug me!
 
MY 28.5 is set up like this.

GP290 head.
Zen stock crank.
Alloy insulator.
813 carb.
Stock filter.
Redneck.
Jetpro silenced pipe like yours.

My L is set around 1-1.25 also with the idle set at 3. I have just started tuning it but can say the plug is still black at the moment. I wonder if its the pipe or carb? Much leaner then the DOM was.

Can't wait to finish getting it tuned up as soon as the weather stops raining and the ground drains.:mad:

Hope you find the issue. Are you sure the throttle cable is pushing it all the way back against the idle screw?
 
Could this be the problem with my monster not wheelieing. I'm sure its not loosin traction on tarmac. Just doesn't semto have the kick to lift front wheels. I have 29cc and mid high ddm
 
i would suggest you reset your L needle to 1 1/4 turns out from fully closed. start the motor, and then adjust your idle needle for a decent idle rpm.

then procede to make SMALL SMALL adjustments to your needles to dial in your tuning.

should reset the H needle to 1 1/2 out from closed at the same time. if your running a ported motor, take the H to 2 out. always start at a known rich setting and tune down to dial it in.

remember these are not nitros. a small small adjustment, sometimes as small as a 32nds movement can make a Huge differance in tuning on both needles.
 
Going out in about 5, to try the different "guides" I have learned from you guys.
Maybe do a few video's as that would be easier to follow.

But something just hit my mind, at some point I have changed out the yellow fuel line
with a black one, the same fuel line type that works as a fuel return.
I see that this black fuel line are smaller then the original yellow one, could this impact the fuel delivery to a point that it makes it worse to tune?
 
Setting the L jet at 1 1/4 forces me to turn the idle screw all the way in to keep the engine running. To make it run good I must set the L needle to about 1 turn out and then I got it to about 1 1/2 turn out on the idle screw.
That gave me this, not much information in this video, as I forgot to tune the H jet, the H jet is here set at 1 1/2 and need to be leaned out a bit I think.

 
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It's pulling great, but popping quite a lot on idle, which sounds very low when it starts to settle there.
IF it's a little rich - popping - then if you lean a SMALL amount on the low, the idle should come up a bit.
Just a very brief idea.
Al.
 
Yes, I have always set my idle a bit to low I think, I keep thinking of it as a 1/1 car and won't it to be real low and slow on idle. But as my friend pointed out last time we where out driving, I should keep the idle a bit higher. What's best, go in on the idle screw or in on the L needle? It's already as low as 1 turn on the L needle.
 
It sounds like you've as much experience as I !!
I've only been into Large Scale for a couple of years - many on this forum have 20+ !!
If you ask me, I'd try it just leaning the low a little and see how it is.
If it's really lean, I suppose it will cut on hard acceleration or hiccup a little - definitely not a good thing!!

Al.
 
I must admit I don't have much experience with tuning engines. I was spoiled with my FG Beetle and HPI Baja 5B. I tuned the engines 1 time out of the box, and never touched them needles again. But I guess I will get the hang of it in the end.
All my other RC's are electro and they don't really need much attention motor wice.
 
I'm running Zenoah 30.5 ESP with a WT-990 carb. The plug part I would need to do a drive to answer ;)
Could I then put in a fresh plug and idle it for a tank on the bench and post up a picture?
 
No, needs to be run. Check out ESP's tuning tip fro checking the spark plug.
I have noticed with my new 813 carb that the (L) has a lower setting then my old 603 and 668's.
 
J-Revo said:
Going out in about 5, to try the different "guides" I have learned from you guys.
Maybe do a few video's as that would be easier to follow.

But something just hit my mind, at some point I have changed out the yellow fuel line with a black one, the same fuel line type that works as a fuel return.
I see that this black fuel line are smaller then the original yellow one, could this impact the fuel delivery to a point that it makes it worse to tune?
Click to expand...


the black line i want to sa is a bit softer than the yellow, so i think it may collapse on itself from the draw of the fuel from carb. i do suggest you at least re install a piece of the yellow fuel line for the intake line. or better yet, but a piece of tygon (gasoline rated hose available at most autoparts stores, and hardware stores/small engine shops like ACE or ACO DIY Hardware stores). Tygon is great fuel line.



J-Revo said:
Setting the L jet at 1 1/4 forces me to turn the idle screw all the way in to keep the engine running. Great! This tells me you are running RICH on the Low needle. so you ll need to make some small tuning adjustments to the L needle by leaning it out a bit, which will raise idle RPM< thus allowing you to back out the idle screw, to lower the idle rpm. you want to be attentive to the low needle position as this needle along with the H needle make AIR/FUEL adjustments thru the carb. you don't want to make it too lean. and the idle screw is just a RPM adjustment feature, not a tuning screw.

To make it run good I must set the L needle to about 1 turn out and then I got it to about 1 1/2 turn out on the idle screw. This is good. just remember the low needle adjust air/fuel mix, the idles screw alows sets the opening for the throatle plate in the carb.
That gave me this, not much information in this video, as I forgot to tune the H jet, the H jet is here set at 1 1/2 and need to be leaned out a bit I think.

http://www.youtube.com/watch?v=ZxDlj6dHe9o
Click to expand...



you dialing it in it sounds like to me.

another good way to tell how the motor is running is by taking the plug out and checking its color, called "Reading the Plug" the color and condition of the spark plugs electrode will tell you ALOT about the motors tuning, and how its running overall.


ya Dougs (ESP) tuning sheet is very easy to follow and understand. he wrote it up well, and you don't need to be an engine builder/tuner to understand it and follow it.
 
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