Today's Message Index:
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1. 06:43 AM - Re: Understanding the Carbmate (lucien)
2. 07:54 AM - Re: Understanding the Carbmate (Roger Lee)
3. 08:19 AM - Gearbox on the 912ULS (Roger Lee)
4. 09:12 PM - Re: Re: Understanding the Carbmate (Karen & Gale Derosier)
5. 10:35 PM - Re: Understanding the Carbmate (Roger Lee)
6. 10:45 PM - Re: Understanding the Carbmate (Thom Riddle)
Message 1
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| Subject: | Re: Understanding the Carbmate |
[quote="madriver42(at)gmail.com"]Tom,
Thanks for your reply. I understand the relationship of throttle to vacuum - But
still am confused as to which carb I should adjust AND when the LED is skewed
left of right does this mean higher or lower vacuum ON WHICH SIDE. I've decided
to use the right Carb as the Master as the cable run is very short and probably
less chance of error. OR question to those who are running a Rotax 912ULS
amI again being anal about adjusting when only one led out???
Phil
> [b]
One LED off is well within a decent balance. It'll be easily taken up by the crossover
tube when you reconnect it anyway. So you're in good shape at that point
as long as it doesn't move off to one side or the other appreciably at different
throttle settings.
IIRC, the relationship I ended up with is to throttle back the carb the LED points
to as I'm holding it in the seat of the plane (engine behind me, pusher config).
If that's not your setup, start by adjusting only one of the carbs to see
which way the LED moves. Memorize that adjustment direction and the direction
the LED moves (or write it on a piece of paper). Then go from there....
LS
--------
LS
Titan II SS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=336909#336909
Message 2
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| Subject: | Re: Understanding the Carbmate |
Pneumatic Carb Balance tips,
First your throttle lever in the cockpit should have a mechanical stop on it of
some kind so when your throttle lever in the cockpit is all the way back at idle
the carb idle stop screw hits it's stop at the same time. This is the most
ideal setup. If you can pull the cockpit lever back any more then you stand a
very good chance at bending the idle stop plates on the carbs.
You should have the plane wheel chocked along with the parking brake set.
If you have to turn your engine on and off because of its configuration then one
person is ok, but 2 still make life easier. If you do your adjustments with
it running 2 people are a must for safety. Making adjustments while it is running
makes life easier, but of course carries more risk of injury so absolutely
take all precautions. I always wear hearing, eye protection (goggles) and never
have loose clothing flapping around.
With the Carbmate or Syncromate you can move the throttle lever on the carb while
it is running to watch which way the light moves and just take note as to how
much before shutting off the engine to make your adjustment. Most adjustments
will be small.
The next big thing I have heard recently is syncing carbs down at 2000 - 2500 rpm
for the high rpm adjustment. This is too low and too close to idle. I never
sync a set of carbs less than 3500 and then check them up to 4000 rpm. If you
set your carb sync up at 2500 rpm I guarantee that at 3500-4000 rpm they will
not be synced. You fly closer to the 3500-4000 rpm and only taxi at 2000-2500
rpm. Your crossover tube can correct up to a certain point, but after that they
will not be synced if you allowed them to be too far out from each other. I
can usually feel carbs out of balance between 4200-4800 rpm in flight on many
planes (not all). Learn your plane and its feel at different rpms. Put your hand
on the frame when you fly and listen to it, get a feel for the way it vibrates
and moves. Then when things aren't right you will know. As the rpms go higher
than 4800 the frequency of the vibration becomes too fine and you may not
feel it any more.
Knowing which carb to change can be a challenge for some.
At idle it is easy. If you are shooting for a final idle rpm of 1750-1800 then
look at your tach. If you are idling at 2000 rpm then adjust the carb with the
lowest number on the gauges because it is getting more fuel and controlling the
rpm more. As you bring down this vacuum to the higher number the other will
change slightly too. If you are only getting 1650 rpm and want to raise the rpm
then adjust the carb with the highest number so it gets more fuel and the gauge
number becomes lower.
The higher the vacuum number on one carb means it is getting less fuel than the
carb with the lower number.
This is the only bad thing about Carbmate and Syncromate as you can't tell which
carb to go after and need to wiggle the carb arms to see which one you want
to adjust. The ideal electronic balancer would have a set of gauges in line so
you could look at the gauge to see which carb to adjust then use the electronic
balancer lights to make it perfect.
As far as adjusting the high rpm for sync and knowing which carb to adjust, I usually
will take a look at the bowden cable screws and see how much adjustment
each has left. I try to adjust the lower number carb getting more fuel to the
higher number carb getting less fuel. Sometimes there is not enough adjustment
left to pull the carb arm back any farther on the one getting more fuel. So
you have to make a decision here. If you only need a little adjustment I may go
ahead and adjust the higher vacuum carb to the lower vacuum carb if it is only
a slight move. If it needs a fair amount then I will adjust the length of the
cable on the one that is pulled back the farthest (getting more fuel, less
vacuum) shortening the cable by 1/16th".
As far as hooking up your gauge or Carbmate lines there are a couple different
ways. For me the easiest and quickest is to pull off the left side crossover tube
on top of the manifold. I put one, smooth, end male fitting in the rubber
tube and I have a female tube that slips over the fitting on top of the manifold.
I do have a screw clamp to snug down on each to prevent any air leaks. No
clamping lines, taking out screws, just no muss or fuss and the carbs are now
separated. Carb balance on the normal plane takes me about 15-25 min. I have had
a couple up around 45 minutes and 1-2 that took an hour+, but that was a long
time ago. Learning when to quit messing with the carbs and make a cable adjustment
right up front can save you 30-40 minutes of time.
The first few carb syncs take a little time and has a learning curve, but after
a few they get easier. Carbs will be out of balance by every 100 hour inspection.
Guaranteed. Cables relax, stretch, pulleys wear, parts in the carb wear,
ect...
BALANCE those carbs and don't let anyone talk you out of it and tell you it isn't
needed. That's as they say is "Hogwash". Think of your engine as a right engine
(cyl 1&3) and a left engine (cyl. 2&4). If one side is getting a little more
fuel than the other it may be trying to run at 5100 while the other side is
trying to run at 5000 (just an example). The cross over can only do so much.
Do it right and sync those carbs. It's only a $20K engine so why screw it up
or shorten its life.
I hope this helps a few.
If you have any questions you can call me.
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Repair Center
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=336911#336911
Message 3
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| Subject: | Gearbox on the 912ULS |
If you have a 912ULS 100 HP with the slipper clutch then you absolutely should
be doing this simple slipper clutch test as out lined in the Line Maint manual
at every inspection. It takes all of 10 minutes and it is vital to the health
of your engine and especially your gearbox. Normal sipper clutch torque is usually
between 440-490 in/lbs. If you get down to around 350 in/lbs I would personally
get the Bellville washers changed and re-shimmed.
This is an easy check and there is absolutely no reason not to do it.
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Repair Center
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=336913#336913
Attachments:
http://forums.matronics.com//files/slipper_clutch_test_531.pdf
Message 4
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| Subject: | Re: Understanding the Carbmate |
Isn't the idea of syncing up mean to match one to the other??? Wouldn't yo
u
just adjust 1 carb to sync to the other??!!!
Gale D.
RANS S6S
On Thu, Apr 14, 2011 at 8:40 AM, lucien <lstavenhagen@hotmail.com> wrote:
> lstavenhagen@hotmail.com>
>
> [quote="madriver42(at)gmail.com"]Tom,
> =EF=BD
> Thanks for your reply.=EF=BD I understand the relationship of throttl
e to
> vacuum - But still am confused as to which carb I should adjust AND when
the
> LED is skewed left of right does this mean higher or lower vacuum ON WHIC
H
> SIDE.=EF=BD I've decided to use the right Carb as the Master as the ca
ble run is
> very short and probably less chance of error.=EF=BD OR question to tho
se who are
> running a Rotax 912ULS am=EF=BDI again being anal about adjusting when
only one
> led out???
> =EF=BD
> Phil
>
> > [b]
>
>
> One LED off is well within a decent balance. It'll be easily taken up by
> the crossover tube when you reconnect it anyway. So you're in good shape
at
> that point as long as it doesn't move off to one side or the other
> appreciably at different throttle settings.
>
> IIRC, the relationship I ended up with is to throttle back the carb the L
ED
> points to as I'm holding it in the seat of the plane (engine behind me,
> pusher config). If that's not your setup, start by adjusting only one of
the
> carbs to see which way the LED moves. Memorize that adjustment direction
and
> the direction the LED moves (or write it on a piece of paper). Then go fr
om
> there....
>
> LS
>
> --------
> LS
> Titan II SS
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=336909#336909
>
>
===========
===========
===========
===========
>
>
--
*Gale Derosier*
Message 5
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| Subject: | Re: Understanding the Carbmate |
Hi Gale,
It is to make the two carbs equal.
If it were only that easy. Once in a while it is that easy and other times it takes
a while trying to dial one or both in. Sometimes you have to make a big adjustment
and you run out of idle stop screw or a cable is too long or too short
and they need adjustment. It all depends if you are having a lucky day and
how well a person maintains their engine.
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Repair Center
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=336969#336969
Message 6
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| Subject: | Re: Understanding the Carbmate |
Phil,
I thought your question pertained to the relationship between vacuum gauge
reading and throttle position. Sorry I can't help on the carbmate lights
because I don't know what the lights on a carbmate do/mean.
Thom in Buffalo
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