Jerry,
OOPS,
I forgot to add that at 450 hours, if you have been running rough for a
while, the needle and its jet tends bang around and wear a bit. Suggest
you change those.
Also, the main jet in my aircraft were 162s. The SB 914-002 was never
accomplished (by the dealer) because the engine ran well. I didn't mic
my jets but went ahead and put in the recommended 160 and 164 jets
recommended on 1/3 and 2/4 respectively. It really helps.
Finally, the float bowl nut mentioned: I still use my old nut, but I
use the fiber and the O ring together to keep the nut from bottoming out
on the main jet. Don't forget to soak your paper gaskets. Torque it
up, then wait overnight and torque again as that pesky O ring tends to
take a set and sure enough at full power at altitude the gasket just may
leak.
Regards,
Bud
----- Original Message -----
From: Bud Yerly<mailto:budyerly@msn.com>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Monday, May 06, 2013 5:41 PM
Subject: Re: Europa-List: 914 rough running
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>
To: europa-list@matronics.com<mailto:europa-list@matronics.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.matron
href="http://forums.matronics.com";>http://forums.matronics.com
href="http://www.matronics.com/contribution";>http://www.matronics.com/c
http://www.matronics.com/Navigator?Europa-List<http://www.matronics.com/N
avigator?Europa-List>
http://www.matronics.com/contribution<http://www.matronics.com/contributi
on>
|