Today's Message Index:
----------------------
1. 01:44 AM - Re: Wandering RPM ()
2. 05:28 AM - Re: New 912 Engine Starting Problem (Thom Riddle)
3. 05:37 AM - [Fw: Release of REVISED MANDATORY Rotax Service Bulletins And NEW Service Instructions For 912 & 914 Series Engines] (Gilles Thesee)
4. 10:34 AM - Re: Wandering RPM (Guy Buchanan)
5. 03:39 PM - Re: Wandering RPM (=?ISO-8859-1?Q?J=F3hann_Gestur?=)
6. 07:40 PM - Re: Wandering RPM (Guy Buchanan)
Message 1
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| Subject: | Re: Wandering RPM |
--> RotaxEngines-List message posted by: <joeing701@internet.is>
Hello Guy.
That all depends on how much air is entering the engine. Most likely it will
increase as you increase the rpm, but if the EGT is approaching 1200 deg F, you
should be on alert.
The EGT will always varie a little, depending on your carb needles and jets. As
you probably know, different rpm effects different needles and jets in the
carb. Lowest rpm=idle jet, mid range=jet needle+needle jet and max rpm=main
jet. The slider groove is also a factor here.
The EGT is the main instrument to monitor the fuel/air mixture. I hope this
will help in solving your problem.
Best regards,
Johann G.
Iceland.
On Tue, 12 Sep 2006 20:02:46 -0700
Guy Buchanan <bnn@nethere.com> wrote:
> --> RotaxEngines-List message posted by: Guy Buchanan <bnn@nethere.com>
>
> At 02:53 PM 9/12/2006, you wrote:
> >When there is excessive air entering the engine via leaky seals, your
> >fuel mixture gets lean and the EGT will rise, which could cause seizure.
> >Your problem is most likely air leak if the rpm is wandering.
>
> How much do you think the EGT will vary?
>
>
> Guy Buchanan
> K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.
>
> Do not archive
>
>
>
>
>
>
Message 2
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| Subject: | Re: New 912 Engine Starting Problem |
--> RotaxEngines-List message posted by: Thom Riddle <jtriddle@adelphia.net>
Hugh,
1) Is the fuel tank valve turned on? I know this is obvious but
sometimes we forget. I have
2) Are both mags on? I've forgotten this one too.
3) Does the fuel pressure gauge read in normal range with just the
electric boost pump on? It should with just the master on and the fuel
pump switch/cb on, and not cranking.
4) When you crank, does the fuel pressure change? With the engine
mechanical pump also doing its job, the fuel pressure reading should be
a little higher than with just the electric pump on.
If 3 & 4 are good, then you know you are getting fuel to the engine,
and the carbs, if there is no leak in the fuel system in the engine
compartment, which would be visually obvious with the upper cowl off.
This also means you are not getting vapor lock anywhere.
If the engine is cold, make sure that the choke is full on and the
throttle is completely closed. When cold the engine will not start if
the throttle is open even a little.
If it still won't start, remove the drip tray under one carb and then
the float bowl to see if the bowl has fuel at the proper level and the
float valve moves up and down okay. While you have the float bowl off,
check to see if the starting circuit jet is loose. The starting jet is
in the bottom of the little vertical cylindrical area in one corner of
the bowl. If it is loose it could affect starting mixture and if it
does start cause rough idling. Do this same thing for the other carb.
and then reassemble carefully making sure you get the bowl gaskets
seated properly.
If after trying all of this it does not crank, let us know and we'll
proceed from there.
Thom in Buffalo
Message 3
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| Subject: | [Fwd: Release of REVISED MANDATORY Rotax Service Bulletins |
And NEW Service Instructions For 912 & 914 Series Engines]
--> RotaxEngines-List message posted by: Gilles Thesee <Gilles.Thesee@ac-grenoble.fr>
Hi all,
As a follow up to our recent discussion on engine, oil and coolant
temperatures, here is the last update sent by Rotax.
The new manuals are downloadable from http://www.rotax-owner.com
Fortunately I had taken numerous data during the flight tests, so
correlating head-temps with coolant temp won't be difficult.
Regards,
Gilles Thesee
Grenoble, France
http://contrails.free.fr
-------- Message original --------
Sujet: Release of REVISED MANDATORY Rotax Service Bulletins And NEW
Service Instructions For 912 & 914 Series Engines
De: updates@rotax-owner.com <updates@rotax-owner.com>
Rpondre : updates@rotax-owner.com
Pour: gilles.thesee@free.fr
Dear Registered User;
The following REVISED MANDATORY SERVICE BULLETINS have been released by Rotax:
SB-912-043
SB-914-029
SB-912-043UL
SB-914-029UL CHANGE OF COOLANT SPECIFICATION ON ROTAX ENGINE TYPE 912 AND 914
(SERIES)
These new Service Bulletins may be downloaded from www.rotax-owner.com
SB-912-043 - http://www.rotax-owner.com/si_tb_info/getdoc.asp?USERID=aiprt&DOCID=SB-912-043&S_TYPE=NW
SB-914-029 - http://www.rotax-owner.com/si_tb_info/getdoc.asp?USERID=aiprt&DOCID=SB-914-029&S_TYPE=NW
SB-912-043UL - http://www.rotax-owner.com/si_tb_info/getdoc.asp?USERID=aiprt&DOCID=SB-912-043UL&S_TYPE=NW
SB-914-029UL - http://www.rotax-owner.com/si_tb_info/getdoc.asp?USERID=aiprt&DOCID=SB-914-029UL&S_TYPE=NW
** Important Note!
Rotax releases separate Service Bulletins for non-certified engine models. These
service bulletins only contain information regarding the non-certified engine
models affected by the service bulletin.
Full service bulletin information and instructions are found in the certified service
bulletin (without the UL designator).
Owners and operators of non-certified engine models must download and review both
the certified and UL versions of the service bulletin to obtain complete service
information.
SB-912-043 R1 /SB-914-029 R1 also requires the revision of several operator's and installation manuals. As service to Rotax Owners Association News users, these manual updates have been posted to the Rotax Owners Association News web site ( www.rotax-owner.com/manualrev/09_11_2006/mrSB9_043_029R1.htm )
------------------------------------------------------------------------------------------------
In addition the following NEW SERVICE INSTRUCTIONS have been released by Rotax:
SI-912-016
SI-914-019 SELECTION OF SUITABLE OPERATING FLUIDS FOR ROTAX ENGINE TYPE 912
AND 914 (SERIES)
These new Service Instructions may be downloaded from www.rotax-owner.com
SI-912-016 - http://www.rotax-owner.com/si_tb_info/getdoc.asp?USERID=aiprt&DOCID=SI-912-016&S_TYPE=NW
SI-914-019 - http://www.rotax-owner.com/si_tb_info/getdoc.asp?USERID=aiprt&DOCID=SI-914-019&S_TYPE=NW
------------------------------------------------------------------------------------------------
Supplemental Information for Rotax Service Bulletins SB-912-043 R1 / SB-914-029
R1
This supplemental information is intended to provide additional background regarding
the changes to the coolant specification as set out in Rotax Service Bulletins
SB-912-043 R1 / SB-914-029 R1.
THIS SUPPLEMENTAL INFORMATION IS GENERAL IN NATURE AND IS NOT INTENDED TO REPLACE
THE INFORMATION PROVIDED IN THE SERVICE BULLETINS.
ALL OWNERS, OPERATORS AND MAINTENANCE PERSONNEL SHOULD OBTAIN AND CAREFULLY REVIEW
THE FULL TEXT OF EACH SERVICE BULLETIN.
After an investigation into a few isolated field reports, it was discovered that
in some instances conventional 50/50 water - glycol coolant mixture could begin
to boil off before the maximum cylinder head temperature was reached.
To address this issue and maintain the highest level of flight safety, Rotax issued
the initial version of Service Bulletin SB-912-043 / SB-914-029 in September
2004. This bulletin changed the coolant specification for the 912 & 914 engines
from a 50 / 50 water - glycol mixture to a 'waterless' coolant with a much
higher boiling point. This change was made to insure that coolant boil off
could not occur in any circumstances provided that the engine CHT limits were
respected.
Subsequent to the initial release of Service Bulletin SB-912-043 / SB-914-029,
Rotax has continued to examine this issue, and now recognizes that for some 912
& 914 engine installations conventional 50/50 water - glycol mixture coolant
may be a viable alternative. Conventional 50/50 water - glycol coolant solution
is inexpensive, readily available and has excellent heat transfer properties.
Understanding the benefits provided by conventional water - glycol coolant in some
applications, Rotax has now released a new revision of Service Bulletin SB-912-043
/ SB-914-029. With the release Service Bulletin SB-912-043 R1 / SB-914-029
R1, use of conventional 50/50 water - glycol coolant is once again allowed,
provided certain conditions can be met.
In order for a 912 or 914 series engine to be safely operated with conventional
water - glycol coolant, SB-912-043 R1 / SB-914-029 R1 mandates that both cylinder
head temperatures AND coolant exit temperature must be monitored at all times.
Coolant exit temperature must never exceed the boiling point of 50/50 water
- glycol coolant mixture AND engine cylinder head temperatures must never
exceed the maximum permissible values set out in the appropriate engine Operators
Manual.
To meet these requirements a coolant temperature sensor and cockpit mounted coolant
temperature gauge must be installed in addition to CHT instrumentation.
The coolant temperature sensor must be installed in the coolant line between the
outlet of the expansion tank and the inlet of the coolant radiator (please
refer to the Cooling System section of the appropriate engine installation manual
for more details). Installation of the coolant temperature sensor must not
impede or restrict the coolant flow. The installed coolant temperature gauge
must be appropriately marked with the maximum allowable coolant exit temperature.
Installation of the coolant temperature sensor and gauge will allow the pilot to
monitor the coolant temperature throughout the entire engine operational range.
If for any reason the coolant temperature approaches or exceeds the maximum
permissible value (approx. 120? C (248? F) in a cooling system pressurized
to 18 psi (1.2 bar)) the pilot will be able to take the appropriate action (reduce
power setting and / or terminate flight).
Once again, installation of a coolant temperature gauge DOES NOT alter the requirements
for the monitoring of engine cylinder head temperatures and respecting
published CHT limits.
In some aircraft installations, the liquid cooling system may not be able to maintain
a coolant exit temperature below the boiling point of conventional 50/50
water - glycol coolant. This may be due to the size of the coolant radiator,
the design of the engine cowling, operating profile, or other related factors.
In applications where the coolant exit temperature may exceed the boiling
point of conventional water - glycol coolant, SB-912-043 R1 / SB-914-029 R1 requires
the use of 'waterless' coolant only.
When 'waterless' coolant is used, monitoring of the coolant exit temperature is
not required. The boiling point of the 'waterless' coolant is higher than the
maximum allowable cylinder head temperature, therefore the coolant cannot be
boiled off without exceeding the engine CHT limits.
Use of 'waterless' coolant DOES NOT alter the requirements for the monitoring of
engine cylinder head temperatures and respecting published CHT limits.
In cases where 'waterless' coolant is used and engine cylinder head temperatures
exceed the maximum permissible values, the coolant system must be repaired or
modified in such a manner as to increase the cooling capacity of the system.
More information regarding coolants for 912 & 914 series engines, including recommended
brand names, can be found in Rotax Service Information SI-912-016 / SI-914-019
(August 2006). All owners & operators of 912 & 914 series engines should
obtain a copy of this Service Information document.
If there is any question regarding the selection of the correct coolant for a particular
engine installation, the engine owner / operator is strongly encouraged
to contact the nearest authorized Rotax Service Center or their aircraft manufacturer.
-----------------------------------------------------------------------------------------------
This e-mail update is provided as a free service to registered users.
Register with Rotax Owners Association News today!
Message 4
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| Subject: | Re: Wandering RPM |
--> RotaxEngines-List message posted by: Guy Buchanan <bnn@nethere.com>
At 01:44 AM 9/13/2006, you wrote:
>That all depends on how much air is entering the engine. Most likely it will
>increase as you increase the rpm, but if the EGT is approaching 1200 deg
>F, you
>should be on alert.
Thanks Johann,
I don't see an increase with RPM, indeed it decreases after the
typical mid RPM peak, so maybe I'm still good. Indeed my EGT's seem good,
within 30 degrees of each other and varying with RPM as recommended. The
only thing I wish is that the manual mixture (HACman) I purchased from
Green Sky had more range.
Guy Buchanan
K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.
Do not archive
Message 5
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| Subject: | Re: Wandering RPM |
--> RotaxEngines-List message posted by: =?ISO-8859-1?Q?J=F3hann_Gestur?= <joeing701@internet.is>
Hello Guy.
This is good. It almost eliminates that air is leaking inside your
engine via seals or rubber sockets, or gaskets(intake-exhaust).
How is the needle sitting in the plastic sledge in your carbs? I have
heard that people install the needle inside the sledge and under the
spring. This can causes the needle to move freely up and down and
therefore give you a wandering rpm. Before you do anything else, check
that. First in order of installation is the needle with the ring
installed sitting inside the cylinder. Then you install the cable, then
the plastic cup/sledge and finally roll the spring onto the cable with
spring sitting inside the plastic cup and sitting inside the groove on
the carb cover.
I hope this explains the installation clearly.
Sorry for not having anything else concrete to solve your problem, but
it can take some time to eliminate the obvious to find the cause.
Best regards,
Johann G.
Guy Buchanan wrote:
> --> RotaxEngines-List message posted by: Guy Buchanan <bnn@nethere.com>
>
> At 01:44 AM 9/13/2006, you wrote:
>
>> That all depends on how much air is entering the engine. Most likely
>> it will
>> increase as you increase the rpm, but if the EGT is approaching 1200
>> deg F, you
>> should be on alert.
>
>
> Thanks Johann,
> I don't see an increase with RPM, indeed it decreases after
> the typical mid RPM peak, so maybe I'm still good. Indeed my EGT's
> seem good, within 30 degrees of each other and varying with RPM as
> recommended. The only thing I wish is that the manual mixture (HACman)
> I purchased from Green Sky had more range.
>
>
> Guy Buchanan
> K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.
>
> Do not archive
>
>
Message 6
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| Subject: | Re: Wandering RPM |
--> RotaxEngines-List message posted by: Guy Buchanan <bnn@nethere.com>
At 03:40 PM 9/13/2006, you wrote:
>How is the needle sitting in the plastic sledge in your carbs? I have
>heard that people install the needle inside the sledge and under the
>spring. This can causes the needle to move freely up and down and
>therefore give you a wandering rpm.
No. It's correct. I even have the little O-ring to keep the needle from
turning.
Guy Buchanan
K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.
Do not archive
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