582 smoother idle!?

[Olle1975]

Hello,

has anybody an idea for a smoother idle?
My engine is shaking at 2000 rpm, by 2800-3000 rpm or more it runs very smooth. Has anybody else this situation or a idea to get smoother, may be changing Idle jet?

Olaf

[Dusty]

First thing is to check your rpm is correct ,the factory tachometer is only a general guide!
Sync your carbs, preferably using the vacuum test.
I run 35 idle jets and have a smoother idle than the 55's
Warmup is still best around 2500rpm but when warm 2000 is ok
The box will start to growl around 1700!
Your idle stop screws may end up screwed right out,so check the throttle slides aren't left hanging(they should both give a dull thunk noise when closed)
You will also notice your EGT'swill be better on finals around 950 rather than flatlined off he scale,it's good to know there is a healthy fire up front if full power is needed in a hurry!

[Av8r_Sed]

What prop are you using? If it has a high mass moment of inertia it'll be tough to get it idling smoothly.

[Olle1975]

Thanks for comments!

I additionally use Tiny Tach for rpm.
The carbs are sync mechanic and pneumatic.
I use the GSC prop, it's not older than 2 years with round about 120hrs.

I run 35 idle jets and have a smoother idle than the 55's
Is the 35 idle smaller than the 55 and the Idle gets leaner? I suspect the idle has to get richer for smoother idle?

You will also notice your EGT'swill be better on finals around 950 rather than flatlined off he scale,it's good to know there is a healthy fire up front if full power is needed in a hurry!
How do you hold up your EGT during Idle in final?

Olaf

[Dusty]

Leaner for a smoother idle and higher EGT.
Rotax seems to set rich at idle, possibly to minimise the risk of getting lean if the prop is driven on descent.
This doesn't seem to be a problem with a 582 in a kitfox but maybe in another application this may change.
Be aware on your first few flights 1200EGT game over!
Also bear in mind an oil injected engine will be getting oil on a lean descent,
Premix will need some oil,so occasional throttle will be prudent

[napierm]

2nd that on the idle jets. I ran the #45 idle jets on the 582. That's with a 3-blade GSC prop on a 3:1 "C" gearbox. Engine would load up and quit on final before that. Same with extended idle on ground. Another help was switching to the iridium tipped spark plugs. The fine wire runs hotter and doesn't foul easily.

[Av8r_Sed]

The GSC prop is pretty light and shouldn't cause any problem idling. +1 on what Napierm and Dusty have said. I have a clutch on mine, so no load at idle. I had to file my carb slides and go to a 35 idle jet.

[Olle1975]

Hello,

to switch on 45 or 35 might be a good idea, thanks!


minimise the risk of getting lean if the prop is driven on descentIf you drive your prop on descent your idlejet hasn't got any task, if you would like to minimize your egt in this situation, you have to change the main jet during full throttle or the setting up the needle during 1/2-3/4 throttle.


first few flights 1200EGT game over1200 is maximum and ok but 1150 will be better, watch at your sparks.


Premix will need some oil,so occasional throttle will be prudent Yes, oilinjection is the better way for idle during descent. I have round about 120 hrs on my engine, it runs great by more than 3000 rpm. I will check to change my idlejet to get a smoother idle, thanks.

Olaf

[Dusty]

Maybe start with 45 jets if you are unsure.
At throttle closed it is still possible to rise the EGT by driving the prop but is unlikely to get dangerous ,with 35's I havn't seen above 1000F
I agree 1200F may be ok but the gauges we use aren't precision instruments,
A plug colour test is a good way to be sure (yours look good 1150 -1200?)
Changing your idle jets effects the lower end of the mid range jetting by a surprising amount!
By changing to 35 idle jets we are deviating a long way from factory settings
Sometimes throwing the text book out the window isn't such a bad thing:D

[Olle1975]

Hi Dusty,

My last sparks, works 25 hrs during winter and spring....

http://www.teamkitfox.com/Forums/attachment.php?attachmentid=9774&stc=1&d=1441728826


Yes we haven't precision instruments, my rpm gauge shows more than Tiny Tach, I hope the egt has the same behavior :-)

In which altitude do you start and fly, my airstrip has only 200ft msl?

I think, first I will srew out my idle-mixture-screw, so I get a leaner mixture too.

Olaf

[Dusty]

Our club field is 180ft and most of my flying is below 3000ft
I use a hacman type mixture controle so height and temp is not an issue but his is really only effective in the mid range(a must have on a 582)
Your idle mixture screw will only give a small change,possibly not enough but it won't hurt to try
Never be afraid to experiment but be careful

[Olle1975]

I use a hacman type mixture controle

Sounds good - show me more, may be a link?

Olaf

[Dusty]

I'm not much on the computer link thing
Google hacman there is plenty of information on line
This setup is very easy to make and install provided you have the later style carbs.
green sky?sell a kit for a reasonable price,it will pay for itself in short time.
To be able to lean our mixture to 1150 and gain 300 rpm at the same time is very satisfying

[Olle1975]

http://www.greenskyadventures.com/bing/HACman_Article.htm

Do you have a handbook or installationguide for copy?

[Dusty]

I don't have any instructions etc but there is more than enough information on line.
The hardest part is finding a compact vernier type flow valve.truck parts/accessory retailers would be a good start.I will try to post a schematic in the next few days

[Olle1975]

Thanks, that's exactly the part I'am intersting in - how to connect the tube and fittings etc.

Olaf

[Dusty]

I have drawn up a diagram and will try to scan and post tonight.
Basically take vacuum from the factory tappings in both carbs to a dash mounted vernier flow valve,then to the float vents which have been linked and vented to the back of your aircleaner.
Note the carbs have to be vented when the mixture controle is turned off,this is one of the reasons the vents go to the aircleaner,
I installed a restricter of 1.5mm (from memory?) to make the controle more sensitive
I found my mid range jetting a little leaner possibly due to the carbs now venting to the aircleaner,so lifted the needles one notch
Job done!

[Dusty]

I hope this is some help. This is from memory as I fitted it some years ago.
The barbed T that goes into the aircleaner is the one that will need a restricter.

[Olle1975]

Thank you very much. I think, you have only one vacuum line from carb!?

I found a few pics from Installation, what do you think?

http://www.avidfoxflyers.com/index.php?/topic/613-hacman-kit-install/

Is it right, that you can lean the mixture only and not set rich?

Olaf

[Dusty]

One vacuum line may work but your mixture controle may be less sensitive?
One quarter turn=200F with my setup
10,000ft needs 3/4 of a turn to maintain 1150F

There is a lot of good information on that site regarding setup

There isn't a rich setting unless you set your carbs rich,the best setting is with the hacman off your EGT's will be slightly rich of ideal so in the circuit, turn it off and forget about it
You will never need a richer setting except in very cold days,best to set your carbs for these days
If you ever encounter high EGT's for any reason(a prop change a while ago caught me out!)remember you can crack the choke slightly and force the temperature down,this simple trick will see you safely back on the strip with no engine damage

[Olle1975]

Hi Dusty,

sometimes I reach the 1200F during travel-configuratiuon with a little descent, hence without propload. In this situation I wish to rich my mixture. I think about to set my needle one notch higher during winter, currently it's set in third Position, second from top.

Olaf

[Dusty]

Sometimes richer is safer then lean back as needed.
11G2 needles will give a Hot spot around 5500rpm made worse by a light load or driven prop.
11K2 (503 dual carb?)helps minimise this

[Olle1975]

You don't think, to set needle one notch higher helps?

[Dusty]

Definitely ,your midrange will be better.

[Olle1975]

I'm bewildered, my needle was set in the second notch, third from top :rolleyes:.
Now I set it in first Position (needle completly high) and the EGT is 1050-1100 F during travel, without propload max. 1150F.
At 5500 rpm it burns 15-16L/hr (EGT 1100), above it rises significantly!!!

Before, I had 5900 rpm 15-16L/hr (EGT 1150) and accordingly more Speed. Without propload I gets 1200F EGT.

Airtemp 12 Grad / 53 F, I'm undecided whether I should use this setting during winter. Last winter I was flown with first configuration (second notch/third from top)

Olaf

[Dusty]

If I understand correctly,you have raised your needle one notch?
This hold give a egt at cruise of 50F lower which it sounds like it has
Coming into winter this would be a good idea,I am unable to explain why last winter the second notch was ok,have any other changes been made?
Needles wear at 200ish hours,but this will a slightly richer mixture!
Has your prop pitch been changed? Check this as some props can walk
I hope this is of some help,and I have the right end of the stick!
(Sorry rushing to get to work site)
A hacman will make life easier:rolleyes:

[jrthomas]

Dusty may have hit on something, the GSC prop. I may have missed something but have you checked the pitch? One of my flyin buddies had a Kolb with a 582 and a GSC prop. He had a problem similar to yours. The problem turned out to be the prop. One blade had changed pitch. He corrected the pitch but it wouldn't stay put. He fixed it by milling a few thousands off the face of the hub, something that's not recommended by GSC. We figured the wooden blades would expand and contract with the weather. The GSC has a pretty short TBO. That could be the reason. Hope you figure it out soon. James Thomas

[Olle1975]

If I understand correctly,you have raised your needle one notch?
Yes I have, before second notch and now first notch.

I am unable to explain why last winter the second notch was ok,have any other changes been made?
No, last winter I checked my temp every minute and fly higher for lower egt, I try to avoid lower altitude and the midrange between 5300-5800 rpm. This year I would like to fly without this limitations and set the needle one notch higher but the consumption is a lot more :o.
My sparks-colour was always good (see other thread), may be my egt measurement shows more than in fact.
Which notch do you use during winter, did you have a change from summer to winter?

We figured the wooden blades would expand and contract with the weather. The GSC has a pretty short TBO Thanks, yes may be. I checked the pitch periodically. My Prop has only 100 hrs and was bought 2013.

Olaf

[Dusty]

Hi Olaf
My setting may not be much help as I am slightly over pitched and the hacman by nature will give a slightly lean from standard setting
My engine log reads as165 jets,2.72needle jet,11k2 needles at 2nd notch from the top.
I don't need to change summer/winter jetting but inflight adjustment is often needed.
Spring weather here!
1500ft -6c egt 1150-1200f , two weeks later same height 18c 1000egt! and needed nearly a half turn on the mixture

[Olle1975]

Hi Dusty,

which pitch do you use?
My GSC and C-Box I have 18 degree at 75%, measure with GSC-Tool and checked with measureapp.
We have the same jets, needle not sure, it's bewildered that you have 1000 egt at 18c at round about 1500ft with second notch from top.
At the same altitude with third notch from top I have 1150 egt.
I check my needle at the weekend....

Olaf

[Dusty]

Not sure of my pitch
but 5900 on runup, 6000 on climb 55 Kts
I don't run the GSC but a arplast helice?
2 strokes and associated instruments are at best a randome thing! The numbers are generally an indication,so direct comparisons are hard to quantify.
Even exhaust mods change the result(putting the exhaust back to stock length gained 150 rpm static.
Just go and have fun:D