Today's Message Index:
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1. 12:59 AM - Re: Bing 64 Idle circuit inlet aperture drilling 3300A (Thruster87)
2. 01:30 AM - Re: Re: Bing 64 Idle circuit inlet aperture drilling 3300A (James, Clive R)
3. 02:01 AM - Re: Re: Bing 64 Idle circuit inlet aperture drilling 3300A (Martin Hone)
4. 02:02 AM - Re: Re: Bing 64 Idle circuit inlet aperture drilling 3300A (Martin Hone)
5. 02:46 PM - Re: Bing 64 Idle circuit inlet aperture drilling 3300A (dons701)
Message 1
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| Subject: | Re: Bing 64 Idle circuit inlet aperture drilling 3300A |
[quote="aerobiz1(at)gmail.com"]Is the LLD you drilled to 1.5mm the air bleed at
the intake bellmouth or the fuel jet in the float bowl that feeds the starting
jet(choke) ?
Yes it was at the bellmouth [small brass orifice intake side bottom].Turning the
mixture screw further clockwise,wouldn't that just lean out the mixture thus
also increasing the temps and with the surging problem it feels like it's not
getting enough fuel?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=363814#363814
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| Subject: | Re: Bing 64 Idle circuit inlet aperture drilling |
3300A
Can you not set the idle mixture with the engine running?
You can find the spread of screw position where it will run smoothly (rich to lean
and back to rich) and then try either end to see what's best when flying.
Certainly a strange one.
Regards, Clive
-----Original Message-----
From: owner-jabiruengine-list-server@matronics.com [mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Thruster87
Sent: 15 January 2012 08:57
Subject: JabiruEngine-List: Re: Bing 64 Idle circuit inlet aperture drilling 3300A
--> <alania@optusnet.com.au>
[quote="aerobiz1(at)gmail.com"]Is the LLD you drilled to 1.5mm the air bleed at
the intake bellmouth or the fuel jet in the float bowl that feeds the starting
jet(choke) ?
Yes it was at the bellmouth [small brass orifice intake side bottom].Turning the
mixture screw further clockwise,wouldn't that just lean out the mixture thus
also increasing the temps and with the surging problem it feels like it's not
getting enough fuel?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=363814#363814
Message 3
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| Subject: | Re: Bing 64 Idle circuit inlet aperture drilling |
3300A
There are two airbleeds if I remember correctly. One is the idle air bleed
on the LH side of the bellmouth, and the centre one feeds the emulsion tube
and needle jet ( this can also be drilled - to 3/16"). Turning clockwise
will reduce fuel flow and thereby lean the mixture. That's why I suggested
at least 2 turns out ( counterclockwise). On a stock set-up, the idle
mixture screw has minimal effect. Drilling out the airbleed helps. Going
to the next size richer idle jet (pilot jet) can help as well ( from say
#35 to #40 )
Marty
On Sun, Jan 15, 2012 at 6:56 PM, Thruster87 <alania@optusnet.com.au> wrote:
> alania@optusnet.com.au>
>
> [quote="aerobiz1(at)gmail.com"]Is the LLD you drilled to 1.5mm the air
> bleed at the intake bellmouth or the fuel jet in the float bowl that feeds
> the starting jet(choke) ?
>
> Yes it was at the bellmouth [small brass orifice intake side
> bottom].Turning the mixture screw further clockwise,wouldn't that just lean
> out the mixture thus also increasing the temps and with the surging problem
> it feels like it's not getting enough fuel?
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=363814#363814
>
>
Message 4
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| Subject: | Re: Bing 64 Idle circuit inlet aperture drilling |
3300A
Have you checked the actual pilot jet ? It is possible that it may simply
be obstructed . Not uncommon to find it blocked or partially restricted.
Marty
On Sun, Jan 15, 2012 at 7:27 PM, James, Clive R <clive.james@uk.bp.com>wrote:
> clive.james@uk.bp.com>
>
> Can you not set the idle mixture with the engine running?
> You can find the spread of screw position where it will run smoothly (rich
> to lean and back to rich) and then try either end to see what's best when
> flying.
>
> Certainly a strange one.
>
> Regards, Clive
>
> -----Original Message-----
> From: owner-jabiruengine-list-server@matronics.com [mailto:
> owner-jabiruengine-list-server@matronics.com] On Behalf Of Thruster87
> Sent: 15 January 2012 08:57
> To: jabiruengine-list@matronics.com
> Subject: JabiruEngine-List: Re: Bing 64 Idle circuit inlet aperture
> drilling 3300A
>
> --> <alania@optusnet.com.au>
>
> [quote="aerobiz1(at)gmail.com"]Is the LLD you drilled to 1.5mm the air
> bleed at the intake bellmouth or the fuel jet in the float bowl that feeds
> the starting jet(choke) ?
>
> Yes it was at the bellmouth [small brass orifice intake side
> bottom].Turning the mixture screw further clockwise,wouldn't that just lean
> out the mixture thus also increasing the temps and with the surging problem
> it feels like it's not getting enough fuel?
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=363814#363814
>
>
Message 5
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| Subject: | Re: Bing 64 Idle circuit inlet aperture drilling 3300A |
Hi
The idle air bleed needs to be drilled to 1.6mm or, .0629, or a 1/16" drill bit
will do. As others have said, turning out is "rich" in "lean".
The idle mixture screw is essentially an adjustable throttle because it controls
the volume of the emulsion of air from the air bleed AND fuel from the idle
jet. What determines rich or lean in the end is actually the relationship between
airflow from the clearance around the throttle blade and the volume of air
and fuel coming from the idle port located just downstream of the throttle blade.
Oddly your troubles seem to start when preparing to land. Besides reduction of
throttle to 2000 rpm, what else is done? Do you turn on the fuel pump? Carb
heat? What is the fuel pressure at this moment? My ultimate guess is that the
engine is at the rich limit such that when pulled to idle the "fire goes out".
What are your exhaust temps at full throttle and cruise? .......DonB
--------
Zenith 701 #76120
Jabiru 2200A #2456 95 hours
Sensenich Wood 64-PJ-36 Prop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=363908#363908
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