Today's Message Index:
----------------------
1. 06:41 AM - Re: Rough Running 912 (Goodone)
2. 07:23 AM - Re: Re: Rough Running 912 (Scott DeMeyer)
3. 07:38 AM - Re: Rough Running 912 (lucien)
4. 09:39 AM - VDO tach installation on 912 (egp8111)
5. 10:23 AM - Re: Rotax revised Service Instruction SI-912-020 / SI-914-022 Re (rampil)
6. 11:22 PM - Re: Re: Rough Running 912 (joeing701@simnet.is)
Message 1
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| Subject: | Re: Rough Running 912 |
The carbs were synchronized pneumatically using the vacuum gage method. This was
done several months back so it might have changed a bit but I don't think that
this is the problem. I normally do my run-up at 3500 rpm and have a drops of
about 100 rpm. Next time out I will take a look at the WOT rpm. However, I do
think that the symptoms remind me of the lean carb problems that we have in
the winter with our two-cycle engines. Raising the needle one notch would normally
fix things with the two-cycle engine. I just didn't think the 912 would be
as sensitive to this. The Lycoming and Continental engines normally don't show
this sensitivity but I viewed one of the Rotex videos last night on adjusting
the needles and this consideration was mentioned as a reason to change the
needle position.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=322454#322454
Message 2
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| Subject: | Re: Rough Running 912 |
I had this exact same problem as well. After spending months trying to fix, rebuilding
carbs, replacing modules replacing wiring etc.... I finally gave up and
took it to the Rotax dealer. He rebuilt the gearbox and the mid-range rough
running problem went away! I would have never in a million years suspected the
gearbox.
Scott
--- On Sun, 12/5/10, joeing701@simnet.is <joeing701@simnet.is> wrote:
> From: joeing701@simnet.is <joeing701@simnet.is>
> Subject: Re: RotaxEngines-List: Re: Rough Running 912
> To: rotaxengines-list@matronics.com
> Date: Sunday, December 5, 2010, 11:21 PM
> --> RotaxEngines-List message
> posted by: "joeing701@simnet.is"
> <joeing701@simnet.is>
>
> Hello Goodone.
>
> This is exactly the same thing my friend has been
> experiencing on his Kitfox. His cure was to change the
> needle jet to the next larger size or from 2,72 to 2.80.
> Solved his problem but as Roger Lee has pointed out, this
> could just be a part of the problem, but the temps are
> normal in the mid range after the change.
>
> Hope this helps,
> Johann G.
> Iceland.
>
> ----- Upprunalegt skeyti -----
> Fr: "Goodone" <goodone41@verizon.net>
> Til: rotaxengines-list@matronics.com
> Sent: Sunnudagur, 5. desember, 2010 19:01:03 GMT +00:00
> Monrovia
> Efni: RotaxEngines-List: Re: Rough Running 912
>
> <goodone41@verizon.net>
>
> Went flying this past Friday and the rough running 912UL
> was back in the mid range (4400-4800rpm) . Not real rough
> but noticeable to me. I have had this problem in the past
> (see beginning of this thread). Note that the rough running
> occurred at the same time of year in the past when the air
> here gets cold (40 F or below). The engine is in sync. Do
> you folks think a change in needle to richen the mixture a
> bit is the answer?
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=322365#322365
>
>
>
>
>
>
>
>
>
>
>
>
> Lists This Month --
> Some AWESOME FREE Gifts!)
> Raiser. Click on
> out more about
> Gifts provided
> www.aeroelectric.com
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> -Matt
> Dralle, List Admin.
> RotaxEngines-List Email Forum -
> FAQ,
> - MATRONICS WEB FORUMS -
>
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>
Message 3
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| Subject: | Re: Rough Running 912 |
Goodone wrote:
> The carbs were synchronized pneumatically using the vacuum gage method. This
was done several months back so it might have changed a bit but I don't think
that this is the problem. I normally do my run-up at 3500 rpm and have a drops
of about 100 rpm. Next time out I will take a look at the WOT rpm. However, I
do think that the symptoms remind me of the lean carb problems that we have in
the winter with our two-cycle engines. Raising the needle one notch would normally
fix things with the two-cycle engine. I just didn't think the 912 would
be as sensitive to this. The Lycoming and Continental engines normally don't
show this sensitivity but I viewed one of the Rotex videos last night on adjusting
the needles and this consideration was mentioned as a reason to change the
needle position.
Yeah it shouldn't be that hair-trigger on the 912. Even at those power settings
you're starting to get into the high-speed mixture circuit which should be compensated
for.
It's a little harder to diagnose on a 4-stroke because it behaves pretty similarly
when too rich or too lean. So it can be hard to tell which it is.
The only installation-related thing I can think of to check is the carb vents (the
overflows on the sides above the intakes); these need to be at the same atmopheric
pressure as the air near the venturies. A common installation error is
to just run the carb vents out into the breeze, i.e. stuff inbetween the carb
bales. If you have the airbox or aircleaners, these lines need to be run inside
them. Don't ask me how I know this and no it wasn't because I was just vigilant
and read the installation manual ;).
So I'm also of the opinion that if you need to change the jetting, particularly
at sea level, there may be another problem. Could be as simple as debris trapped
in one (or even both) of the carbs.
I live at 7000' MSL and kick around the patch at 10,000' MSL and my carbs only
run slightly rich at the usual 2000-2500 rough spot with the factory jetting.
I also have to lean out the idle mix. Otherwise, they're acceptable at 3500rpm
and above....
LS
--------
LS
Titan II SS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=322464#322464
Message 4
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| Subject: | VDO tach installation on 912 |
does anyone have the wiring diagram for the VDO tach for the 912 ?
thanks
EG
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=322481#322481
Message 5
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| Subject: | Re: Rotax revised Service Instruction SI-912-020 / |
SI-914-022 Re
Most of the factory-line improvements are strictly optional, at least
2 deal with inability of the factory to get discontinued parts, so new parts
and fittings are spec'd. If you already have an engine, then you have the
sensors in question and do not need replacement (unless they break).
No need to change working fuel lines either as the SI notes.
Actually I did not see anything that was mandatory, or even recommended
in this list, but I could be wrong ;)
Cheers,
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=322485#322485
Message 6
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| Subject: | Re: Rough Running 912 |
Hi Scott.
When you had this engine rough running problem, did you notice any change or difference
in the exhaust temp between cyl?
Regards,
Johann G.
Iceland.
----- Upprunalegt skeyti -----
Fr: "Scott DeMeyer" <scottsr1100rt@yahoo.com>
Til: rotaxengines-list@matronics.com
Sent: Mnudagur, 6. desember, 2010 15:19:19 GMT +00:00 Monrovia
Efni: Re: RotaxEngines-List: Re: Rough Running 912
I had this exact same problem as well. After spending months trying to fix, rebuilding
carbs, replacing modules replacing wiring etc.... I finally gave up and
took it to the Rotax dealer. He rebuilt the gearbox and the mid-range rough
running problem went away! I would have never in a million years suspected the
gearbox.
Scott
--- On Sun, 12/5/10, joeing701@simnet.is <joeing701@simnet.is> wrote:
> From: joeing701@simnet.is <joeing701@simnet.is>
> Subject: Re: RotaxEngines-List: Re: Rough Running 912
> To: rotaxengines-list@matronics.com
> Date: Sunday, December 5, 2010, 11:21 PM
> --> RotaxEngines-List message
> posted by: "joeing701@simnet.is"
> <joeing701@simnet.is>
>
> Hello Goodone.
>
> This is exactly the same thing my friend has been
> experiencing on his Kitfox. His cure was to change the
> needle jet to the next larger size or from 2,72 to 2.80.
> Solved his problem but as Roger Lee has pointed out, this
> could just be a part of the problem, but the temps are
> normal in the mid range after the change.
>
> Hope this helps,
> Johann G.
> Iceland.
>
> ----- Upprunalegt skeyti -----
> Fr: "Goodone" <goodone41@verizon.net>
> Til: rotaxengines-list@matronics.com
> Sent: Sunnudagur, 5. desember, 2010 19:01:03 GMT +00:00
> Monrovia
> Efni: RotaxEngines-List: Re: Rough Running 912
>
> <goodone41@verizon.net>
>
> Went flying this past Friday and the rough running 912UL
> was back in the mid range (4400-4800rpm) . Not real rough
> but noticeable to me. I have had this problem in the past
> (see beginning of this thread). Note that the rough running
> occurred at the same time of year in the past when the air
> here gets cold (40 F or below). The engine is in sync. Do
> you folks think a change in needle to richen the mixture a
> bit is the answer?
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=322365#322365
>
>
>
>
>
>
>
>
>
>
>
>
> Lists This Month --
> Some AWESOME FREE Gifts!)
> Raiser. Click on
> out more about
> Gifts provided
> www.aeroelectric.com
> www.buildersbooks.com
> www.homebuilthelp.com
> -Matt
> Dralle, List Admin.
> RotaxEngines-List Email Forum -
> FAQ,
> - MATRONICS WEB FORUMS -
>
>
>
>
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