Today's Message Index:
----------------------
1. 05:04 AM - Re: Rough Running 912 (Thom Riddle)
2. 06:55 AM - Re: Re: Rough Running 912 (Hugh McKay)
3. 07:28 AM - Re: Rough Running 912 (lucien)
4. 08:02 AM - Rotax Oil Filters changing, new part number assigned (Roger Lee)
5. 11:04 AM - PROP CONTROL (ROBERT LINDSAY)
6. 01:07 PM - Re: Rough Running 912 (Thom Riddle)
7. 02:04 PM - Re: Re: Rough Running 912 (Hugh McKay)
Message 1
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| Subject: | Re: Rough Running 912 |
FWIW, the standard vent line location for the Bing 94 CV carb on Jabiru engines,
similar to the Bing 64 carbs on the 912 series, is to the inside of the K&N
filter if the engine is not fitted with an airbox. Mine, and every other Bing
94 I've seen without an airbox, has a 90 degree elbow fitted into the end of the
K&N filter with the vent line connected to that.
I know Jabiru and Rotax are different, but functionally, the Bing 64 and 94 carbs
are essentially identical and require the same venting. Without an air-box,
the only way to ensure the proper vent line location (in my opinion) is to route
it into the filter. I would suggest it is even more important on a Rotax since
they have two carbs with critical balance requirements.
I doubt seriously that this would cause rough running symptoms but it is a factor
that should be dealt with properly, if for no other reason than to eliminate
it from the mix of variables.
--------
Thom Riddle
Buffalo, NY (9G0)
Kolb Slingshot SS-021
Jabiru 2200A #1574
Tennessee Prop 64x32
Everyone is entitled to his own opinion, but not his own facts.
Daniel Patrick Moynihan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=323520#323520
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| Subject: | Re: Rough Running 912 |
Thom, Lucien:
This discussion is very interesting. My 912 UL came new from Rotax with the
carb vent lines neatly tucked behind the bowl clip and run down to just
above the little pans under the carb bowl. I now have 400+ hours on the
engine. I may be mistaken (or just ignorant of the fact) but to my knowledge
Rotax doesn't address this issue at all. I fly from a field elevation of
1035 ft. msl, and fly down to sea level on numerous occasions, and then at
times up to 8500 ft. msl to cross over the Appalachian mountains. I have not
had any obvious engine/carb problems that I know of. However I do notice
that when changing plugs they seem to be too "black", and not the nice
"brown" color everyone talks about. So Thom, if I am hearing you correctly,
in your opinion I should route each vent line back into it's respective air
filter. Did you do this on your old 912 UL (The Allegro 2000), and if so how
did you do it? Did you ever operate the engine with the vent lines as they
come standard from Rotax?
Hugh McKay
-----Original Message-----
From: Thom Riddle
Sent: Thursday, December 16, 2010 8:01 AM
Subject: RotaxEngines-List: Re: Rough Running 912
FWIW, the standard vent line location for the Bing 94 CV carb on Jabiru
engines, similar to the Bing 64 carbs on the 912 series, is to the inside of
the K&N filter if the engine is not fitted with an airbox. Mine, and every
other Bing 94 I've seen without an airbox, has a 90 degree elbow fitted into
the end of the K&N filter with the vent line connected to that.
I know Jabiru and Rotax are different, but functionally, the Bing 64 and 94
carbs are essentially identical and require the same venting. Without an
air-box, the only way to ensure the proper vent line location (in my
opinion) is to route it into the filter. I would suggest it is even more
important on a Rotax since they have two carbs with critical balance
requirements.
I doubt seriously that this would cause rough running symptoms but it is a
factor that should be dealt with properly, if for no other reason than to
eliminate it from the mix of variables.
--------
Thom Riddle
Buffalo, NY (9G0)
Kolb Slingshot SS-021
Jabiru 2200A #1574
Tennessee Prop 64x32
Everyone is entitled to his own opinion, but not his own facts.
Daniel Patrick Moynihan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=323520#323520
Message 3
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| Subject: | Re: Rough Running 912 |
hgmckay wrote:
> Thom, Lucien:
>
> This discussion is very interesting. My 912 UL came new from Rotax with the
> carb vent lines neatly tucked behind the bowl clip and run down to just
> above the little pans under the carb bowl. I now have 400+ hours on the
> engine. I may be mistaken (or just ignorant of the fact) but to my knowledge
> Rotax doesn't address this issue at all. I fly from a field elevation of
> 1035 ft. msl, and fly down to sea level on numerous occasions, and then at
> times up to 8500 ft. msl to cross over the Appalachian mountains. I have not
> had any obvious engine/carb problems that I know of. However I do notice
> that when changing plugs they seem to be too "black", and not the nice
> "brown" color everyone talks about. So Thom, if I am hearing you correctly,
> in your opinion I should route each vent line back into it's respective air
> filter. Did you do this on your old 912 UL (The Allegro 2000), and if so how
> did you do it? Did you ever operate the engine with the vent lines as they
> come standard from Rotax?
>
> Hugh McKay
>
> --
Yeah, this is a little-known fact of the Bing 64's. Like I said, mis-installed
lines don't seem to create a noticeable problem at lower altitudes. Also, since
the airbox is often eliminated and filters only are used, it's just one of those
installation errors that kind of goes unnoticed.
The installation manual is, of course, the oh-so-wonderful translation from German,
so a lot of the wording in it just sounds strange and isn't entirely clear.
Now why Bing chose to design the carb that way, who knows. It seems kind of silly
to me but carbs are kind of black magic anyway so I just follow the instructions
and hope for the best ;).
BTW, as jetted from the factory, there's a rich spot in the 2000 to 3500 rpm range
and the factory idle mix setting of 1.5 turns is, in my experience, overly
rich (and WAY too rich at my altitude). So black plugs after an extended idle
back to the hangar is kind of par for the course.
The thing I look for is a nice, antique white baffle in the exhaust which indicates
adequately lean running at full power. I check this with a flashlight at
my post-flight every time.....
LS
--------
LS
Titan II SS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=323541#323541
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| Subject: | Rotax Oil Filters changing, new part number assigned |
Revision #2
New oil filter part number correction
by XatorMan under ROTAX PRESS RELEASESRotax has just released the informaiton on
the oil filter minor changes. In the release they inadvertently gave out the
wrong part numbers. Owners and operators and service providers will be recieving
the new filters under 2 different part numbers, depending on the ordering
scope. (by bulk or individual) Please note the following change from the release
of December 3rd.
Part number 825710 and 825712, changed to 825010 and 825012 respectivly. This will
be the new numbers the filter will be supplied with.
It is worth repeating that all users should check the installaitons and confirm
that the small change in the length of the filter, as shown in the drawing supplied
from December 3rd, be verified. While it is not anticipated that this will
have any ill effects the clearance, especially to the exhaust system on number
2 cylinder, has to be considered.
Contact your independent Rotax distributor or independent Rotax Service Centre
for any additional information.
Drawing is not to scale:
No tagsLeave a Commentmore...
3
Dec/10
Revision #1
Rotax Oil Filters changing, new part number assigned
by XatorMan under ROTAX PRESS RELEASESRotax; BRP-Powertrain, is making a minor
change on the oil filter for ROTAX 912 and 914 Series engines.
Production of the current oil filters part no. 825704 and 825706 has been discontinued,
once stock is depleted they will be not longer available.
The replacement filters will have a new part no. 825710 and 825712, internally
they are the same and they have been approved from engineering, however one small
change has to be noted. The overall length has increased about 3.5 mm ( .138
) due to the production process. For detailed dimensions see attached sketch.
OEM and end use customers need to check and make sure they have clearance and make
any necessary changes to accommodate this new filter. The part will be coming
in the first quarter of 2011.
New production filter for 9 Series Rotax engines, early 2011
- Image provided as a reference only. Image is not to scale.
new oil filter, rotax
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Repair Center
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056
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http://forums.matronics.com/viewtopic.php?p=323550#323550
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I have a Czech made (Woodward type) governor which works fine in the air
controlling my C/S Whirlwind prop on a Rotax 914 (almost 600 hrs). But
recently I have not been able to get an rpm drop during a pre-TO check
at 4000 rpm. Oil is clean and warm. Even a post flight check results
in no rpm drop when cockpit control is fully retarded.
Any ideas before I start de-cowl and disassemble?
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| Subject: | Re: Rough Running 912 |
Hugh,
We ran our Allegro with vent lines tucked into the float-bowl bail too for the
entire time we owned it, with no problems either. It is not essential to change
that in any way as long as you don't have any really odd airflow under the cowl
and therefore unusual pressure distributions. However, routing the vent line
to the inside of the air filter is the way that Jabiru does theirs and it does
eliminate any spurious pressure issues that might arise in some installations.
As Lucien said, black plugs are common after a few minutes of low rpm running.
The only way to get an accurate plug reading on engines with Bing CV carbs is
to cut the engine off at altitude at cruise rpm, do a dead stick landing and check
the plugs. I am not recommending this, of course, though I have done it myself.
--------
Thom Riddle
Buffalo, NY (9G0)
Kolb Slingshot SS-021
Jabiru 2200A #1574
Tennessee Prop 64x32
Everyone is entitled to his own opinion, but not his own facts.
Daniel Patrick Moynihan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=323600#323600
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| Subject: | Re: Rough Running 912 |
Thom,
Thanks. Based on my operating experience and engine performance to date, I
see no reason to start re-routing my vent lines. However, the information
gleaned from the input from you and Lucien has been very helpful in better
understanding the operating characteristics of the 912 UL.
Hugh McKay
Maiden, NC
Allegro 2000
Rotax 912 UL
-----Original Message-----
From: Thom Riddle
Sent: Thursday, December 16, 2010 4:04 PM
Subject: RotaxEngines-List: Re: Rough Running 912
Hugh,
We ran our Allegro with vent lines tucked into the float-bowl bail too for
the entire time we owned it, with no problems either. It is not essential to
change that in any way as long as you don't have any really odd airflow
under the cowl and therefore unusual pressure distributions. However,
routing the vent line to the inside of the air filter is the way that Jabiru
does theirs and it does eliminate any spurious pressure issues that might
arise in some installations.
As Lucien said, black plugs are common after a few minutes of low rpm
running. The only way to get an accurate plug reading on engines with Bing
CV carbs is to cut the engine off at altitude at cruise rpm, do a dead stick
landing and check the plugs. I am not recommending this, of course, though I
have done it myself.
--------
Thom Riddle
Buffalo, NY (9G0)
Kolb Slingshot SS-021
Jabiru 2200A #1574
Tennessee Prop 64x32
Everyone is entitled to his own opinion, but not his own facts.
Daniel Patrick Moynihan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=323600#323600
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