Bob,
Try Googling "Dowty washer" an old fashioned idea that works!- and much to
my surprise, they make them in metric sizes.
Regards
Brian Davies
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Bud Yerly
Sent: 19 May 2013 18:03
Subject: Re: Europa-List: 914 rough running
Jerry,
The idea of using an O-ring is cheap for Rotax, but without lube, the O-ring
is going to squeeze out poorly, and can even roll over themselves under
torqueing. The proper seal would be a flat rubber or compression washer or
design a bolt with a curved recess for the O-ring. There is nothing in the
industry that makes such a bolt for sealing with an O-ring, only way to seal
quickly and inexpensively to a flat surface is a flat washer. My
understanding is that the new bolt is slightly longer and allows the jet to
not bind on the bolt recess as it did on the older 914s. If you use the
O-ring without the fiber washer the bolt will impact the jet and bind or cut
off fuel supply. Other than that, they are the same.
Just lube the O-ring and torque to spec, then wait a day and torque again,
it holds very well.
My plane is down until Rotax can get me another stainless fuel line. After
numerous removals of my carbs, the right carb compression fitting no longer
seals. $178 bucks and it will be 6 weeks. Lockwood is trying to locate one
or a set in the US.
I think I would be happy with a 912S. Push on barb fittings are a pain, but
hose is fairly cheap, reliable and easily replaced. As I get older, I like
simple. Planes in our shop get the easiest to change fittings and hoses I
can find. I could care less if a hose has to be cut off the barb and be
replaced, as I make sure I have access to all my hoses. I use quick
disconnects from CPC for my fuel filters for rapid and cheap filter changes.
Just keep extra O rings.
Regards,
Bud
----- Original Message -----
From: Jerry Rehn <mailto:rehn@rockisland.com>
Sent: Saturday, May 18, 2013 2:56 PM
Subject: Re: Europa-List: 914 rough running
Bud
After about 4 tries the oring has an even fit!
Sent from my iPad
On May 17, 2013, at 8:08 PM, Jerry Rehn <rehn@rockisland.com> wrote:
Bud
I have the new float chambers and new orings for the retraining nut and now
see the oring wants to buldge out a bit on torquing down. I assume the new
revised bolt has provisions for the oring that the current bolt does not.
You indicated that yours worked ok. I am hoping to not have to purchase the
new bolts at about $80 each!
But I am not happy with the oring not fitting perfectly. I see you left the
old washers in place as well, I don't see how that will keep the oring from
pressing out. I torqued down to only 46 inch. I didn't lube them, thought
this would make it worse? Tomorrow I will try some lube but welcome any
other suggestions.
Thanks
Regards
Jerry
Sent from my iPad
On May 6, 2013, at 2:41 PM, "Bud Yerly" <budyerly@msn.com> wrote:
Jerry,
Please note that the 914 is a bugger to troubleshoot, and all the advice so
far is notable and spot on.
Since the engine has two problems: (1) Rough after pulling it back and (2)
TCU Caution light, I will deal with 2 first...
2. The caution light is most probably your throttle pot is not hooked up
electrically or the pot was not set to idle with the throttle plate closed
so check your connections and pot rotation after doing the carb. Easy
mistake, especially since the book doesn't cover it. If not set properly,
the TCU gets the wrong throttle position for the Turbo boost and pressure
sensors.
1. With you having the same hours I have on my engine, I have noticed that
with all the tubing and carb float bowl items operating properly and no fuel
leaks, the engine on power reduction runs very rough but idles well and runs
well above 4000 RPM. I suspect yours is similar.
It is not uncommon that one of the carb pistons is hanging up. Once the
piston goes up on full throttle, one doesn't want to come down. I removed
the carburetors again. I completely drained and freed both my carbs of fuel
to prevent an explosion. I rigged my vacuum cleaner and pulled air from the
manifold side and noted the movement of the piston. On the left carb it was
clearly hanging up. After much cleaning, sanding with 1000 and 1500 grit
paper, polishing and more cleaning, the piston is acceptable in its movement
and smoothness. If your carb pistons move smoothly and in unison (checked
by noting the throttle angle vs piston position) then that should make the
carbs balance in the mid range. If the main carb body is worn or scored
badly, some small grit has gotten into the carb and I am afraid you can
save a lot of time and trouble by buying two new carbs. By the way, that is
about the price of a small car down payment.
To Bob Borgers comment, I have found that leaving the float bowl gasket in
place and adding the new extra O ring (with a bit of lube) allows me to
install the original float bowl attachment screw and I torque it to 48 inch
pounds. Be sure to soak your paper gasket in fuel for a few minutes. Note
that the old manual said 5.5 nm or 45 foot pounds. Obviously 45 foot pounds
is going to seriously bend the bottom of the carb bowl and the pins.
Luckily, a quick $100 per float bowl will fix that. I have found that it
necessary to pay attention to the translation and conversions in the old
manual. The new manual has the torque hidden in the verbage so well that I
had to post it to my board in the shop. Please pay close attention to your
brass float pins and the float bowl. Also make sure your float needle valve
and arms are undamaged.
I have been very disappointed in the fit of the new carb parts such as the
needle fixation screw with the O ring. It sucks.
I hope your carbs just need a little tender love and care and not
replacement. I am at my last straw with my 1/3 side carb, so I may be
spending some big bucks.
Regards,
Bud Yerly
----- Original Message -----
From: Jerry Rehn <mailto:rehn@rockisland.com>
Sent: Sunday, May 05, 2013 3:43 PM
Subject: Europa-List: 914 rough running
A little history. Engine has about 450 hours, always ran quite well,
replaced upper ignition module about two years ago.
On recent full boost takeoff, got to about 900 feet leveled off, pulled
throttle back and engine ran severe rough, pulled back to idle and engine
ran ok, didn't stop! Landed. Checked fuel filter, ok, looked for anything
around carbs, nothing. Tried several full run ups, ok. Tried second take off
everything fine, pulled back and again engine ran severe rough, pulled back
to idle, ran rough, landed. Parked plane, got tools, next day removed carbs
looked for issues. Found one of the four screws that holds down the rubber
diaphragm loose, very strange because I have never removed this before.
Anyway figured this was my problem. Fixed took off all ok. Got home. Next
day tried full boost, same issue again, didn't take off. Got carburetor
repair kit and went through both carbs. Reinstalled carbs double checked.
Started right up, as I move the throttle past 2300 rpm the yellow caution
light starts blinking, engine runs rough, reduce rpm the light goes off,
increase the light comes back on. Seems the engine runs off the idle jet ok
but not on the main jet.
I have also checked the waste gate for proper function, fuel pressure ok,
turbo lights come on and go off as they should when master is tuned on, I
have looked at the vent lines. The yellow blinking light can indicate a
sensor failure, seems like it would continue blinking if there was a
failure. Seems odd that it stops at low rpm. Seems I have some kind of a
vacuum or pressure issue, but am running out of ideas. I am about to go and
recheck again! Could a faulty sensor cause this?
Hope someone out there has some wise thoughts on this frustrating problem.
Worse yet, we have beautiful spring flying weather!
Thanks for help.
Jerry
914 Mono XS
href="http://www.matronics.com/Navigator?Europa-List";>http://www.matronhref
"http://forums.matronics.com";>http://forums.matronics.com
href="http://www.matronics.com/contribution";>http://www.matronics.com/c
D========================
===================
a-List"">http://www.matronics.com/Navigator?Europa-List
D========================
===================
//forums.matronics.com
D========================
===================
ot;">http://www.matronics.com/contribution
D========================
===================
href="http://www.matronics.com/Navigator?Europa-List";>http://www.matronhref
<http://www.matronhref=%22http:/forums.matronics.com%22%3ehttp:/forums.matro
nics.com> "http://forums.matronics.com";>http://forums.matronics.com
href="http://www.matronics.com/contribution";>http://www.matronics.com/c
No virus found in this message.
Checked by AVG - www.avg.com
|