.15 nitro engine IDLE problem!

I have a .15 nitro engine and I can't get my engine to run on idle because it stops immediatly decresing RPMs.

When I have it running on "my idle" (the 1/2 of the throttle) and want to accelerate quite smoothly , it does the same thing. It stops.

I have to accelerate very very smoothly and wait for it to respond.

Which needle must I adjust?

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.15 nitro engine IDLE problem!

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May 19, 2009
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Thanks!
by: George

Ok!
I will correct a very little the engine for an idle at 0% of the trim (if I can).

and the fuel now is burning much better without drops on the ground!

I will now buy a camera for the helicopter and start to explore the nature!

May 18, 2009
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Awesome!
by: Matt

That's great to hear George! Have fun flying!

May 18, 2009
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A Greate THANKS!!!~
by: George

Thank you everyone!!!
Thank you for your help.

I did it! I got my engine run very well!!!

Now I have a good "relanti" (french) it is the idle and a nice acceleration from idle to full throtle. The idle is a litle bit high. I had to open some the trim of the throtle. it is about the 3/4 of the trim and I get a nice idle.

Maybe I have to adjust it a litle bit more for a perfect idle at the 0 of the trim.

Thank you anyway!!! I can see the smoke getting out from the muffler.

May 17, 2009
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Thanks.
by: George

Thanks, I'll try it and don't worry.. I'll get it run.

If I go to a modelism shop, can the man make it?
Well, I'll try alone first.

Anyway,
1) I try to get the max RPMs at full throttle with the high speed needle AND OF COURSE WITHOUT STALLS...

2) I adjust the low speed needle for more RPMs and a possible lower gas.

3) I readjust the high speed needle because of the low speed needle change.

4) I get everything from the beginning until I get the optimal RPMs at full throttle and a low IDLE at 0% gas (of the transmitter).

5) I turn the high speed needle to richen it for about 200 - 300 RPMs down.

I'm ready! Thanks!!!

May 17, 2009
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Basic Tuning
by: Michael from Oz

G'day

Sounds like you need to go back to basics. Try this. The two needles do interact with each other. The low speed needle acts over about 2/3 of the throttle range.

1. Get it running. Take it to full throttle and tune it for maximum revs.
2. Go to as low an idle as you can get. Adjust the low speed needle for best revs at that setting.
3. Go back to full throttle and re-adjust for max revs. It is generally best to first adjust a bit rich and then adjust for max revs.
4. Repeat the low speed adjustment as before.

Keep doing this until you get a reliable idle with a good transition. Then adjust the high speed needle slightly rich (a drop of about 200 to 300 revs).

Each time it should get better and idle a bit lower.

If it does not. Try some fresh fuel. There is nothing worse for giving a bad idle than fuel which had picked up moisture. Your fuel is METHANOL not Nitro. The Nitromethane is an additive to help make tuning easier and add a bit of power. Methanol will absorb water from the atmosphere and it wrecks the fuel for idle.

May 17, 2009
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Engine type.
by: George

The engine came with the Nitro Kestrel SE from Century UK.

http://www.centuryuk.com/Products/Ready+To+Fly+Radio+Control+Helicopters/item3080?startPos=

I don't know the engine. I'll send an E-Mail in the evening because I have to go now.

Bye!
Have nice flights!

May 16, 2009
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what is the engine
by: Matt

What brand is the engine?

Best bet is to set it back to factory settings and see how it acts.

May 16, 2009
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Yes but the fuel?
by: George

If I richen it, will the fuel stop to make drops in the ground? Oh, and I didn't tell you!
~ I can't have the engine to idle at full throttle down. I must have the throttle to more or less at 40 to 50% of the gas to keep it running!!!

ANY IDEAS ON HOW TO MAKE IT IDLE?????

Is the high speed needle obligatory to be correctly adjusted to adjust the low speed needle?

To adjust the high speed needle, I have a method that I don't know if it is good.

I try to adjust it so I can put the throttle at 100% of the gas and it doesn't stops. I think that I will try to adjust the 100% throttle and only after that, the low speed and I think that it will be allrite.

Any suggestions on how to adjust the engine FROM THE BEGINNING???

After all these settings, I think that I lost the default settings. I will try with the method as described above.

May 16, 2009
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Too lean????
by: George

It can spray the ground with the mixture that I have!!! And the fuel goes VERY VERY FAST!!!

If I turn it more rich, it will not even burn the fuel.

May 16, 2009
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Thanks. but...
by: Georges

I think that it is to rich. there's no big smoke from the exhaust... and listen...

When I turn the high speed needle CLOCKWISE there's enough smoke and everything seems good but when I fly the helicopter for some seconds, the main rotor seems to be vulnerable. It slows down very little and I have to accelerate to keep it running.

That's a problem that normally appears in a too lean mixture, and the fuel is emptying normally.

Why when I richen it the smoke stops appearing?

When I turn the high speed needle counter-clockwise richen it, the engine has no problem (power, speed) but the fuel is emptying very fast and I can see fuel dashes in the ground made from the exhaust and while idleing, the exhaust sprays the ground in some sec.

You can see the wasted fuel in form of spraid gas.
I try to get a middle answer but... not as perfect as I need.

Is there a setting for the low speed needle while I adjust the engine with the first method so the engine doesn't slows down (a very little)?

It starts to slow down after 10-15 sec in the air.

May 16, 2009
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Lean engine
by: Bill

Always start with the main needle adjustment on the venturi (carburator) first and after starting the engine gradually open the needle until it runs rich (4 cycling) and then slowly turn the needle in until it goes to 2cycling.

You should see or feel the white mist coming out of the exhaust. If it ever turns grey or black you are damaging the engine. It won't be critical as long as you open to a richer setting immediately.

Then you can work on the idle screw which should be on the opposite side of the carb. If it will idle at all you can make very small adjustments until you get the idle you want. If it idles you can pinch the fuel line and if it dies right away the idle is too lean and if it continues to run and then speeds up before it dies it's too rich.

You need to make your adjustments while the engine is stopped for safety sake which will require you to start the engine several times until you get the result you want. You may have to make a small adjustment to the main needle valve after you get the idle setting, it just depends on whether it gets too lean or rich but the final result should be slightly on the rich side.

Please don't try to squeeze out the last rpm you can because it won't make any noticeable difference in speed (power) but as the fuel gets lower in the tank your engine will naturally start to lean out and you don't want that.

Remember, if the exhaust turns grey or black you need to throttle back and land as soon as you can to make an adjustment.

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May 16, 2009
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Submitted by: Bill

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Always start with the main needle adjustment on the venturi (carburator) first and after starting the engine gradually open the needle until it runs rich (4 cycling) and then slowly turn the needle in until it goes to 2cycling. You should see or feel the white mist coming out of the exhaust. If it ever turns grey or black you are damaging the engine. It won't be critical as long as you open to a richer setting immediately. Then you can work on the idle screw which should be on the opposite side of the carb. If it will idle at all you can make very small adjustments until you get the idle you want. If it idles you can pinch the fuel line and if it dies right away the idle is too lean and if it continues to run and then speeds up before it dies it's too rich. You need to make your adjustments while the engine is stopped for safety sake which will require you to start the engine several times until you get the result you want. You may have to make a small adjustment to the main needle valve after you get the idle setting, it just depends on whether it gets too lean or rich but the final result should be slightly on the rich side. Please don't try to squeeze out the last rpm you can because it won't make any noticeable difference in speed (power) but as the fuel gets lower in the tank your engine will naturally start to lean out and you don't want that. Remember, if the exhaust turns grey or black you need to throttle back and land as soon as you can to make an adjustment.

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May 16, 2009
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I secend that observation, it's too lean.
by: Matt

Definitely sounds like its too lean.

You really need to check the adjustment on both the high and low end needles.

Running the high end too lean will damage the engine, even if it does seem to be running OK.

The caster oil in the fuel is what keeps everything lubricated. When the engine is running too lean it is not getting enough cooling or lube and will damage the engine.

If you can tell us exactly what engine it is, we can probably find the manual online for you if you don't already have it.

Good luck!

Matt

May 16, 2009
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lean
by: Anonymous

It's too lean. You didn't mention which .15 nitro engine this is, airplane, marine, or car, but you can refer to your owners manual and locate the idle mixture screw on the carb and richen the adjustment.