Today's Message Index:
----------------------
1. 03:21 PM - Rough running 2200 (Chuck Deiterich)
2. 03:47 PM - Re: Rough running 2200 (Jabiru USA)
3. 08:20 PM - Re: Rough running 2200 (Peter Harris)
Message 1
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| Subject: | Rough running 2200 |
1. Several flying hours ago my 2200 (solid lifters-#988) started running
rough at full throttle (~3140 rpm) and a bit rough about 3000 rpm (95
total hours). The float bowl was running over. My float needle was the
one with the weak spring so I put in a new float needle with the
stronger spring. Now, no fuel running over, engine off with Facet fuel
pump for several minutes.
2. Engine still is rough at high throttle, I thought it might be rich so
I installed 4 EGT probes 120 mm from exhaust faces before changing any
jets. My main jet is 255.
3. At 2800 rpm all 4 cylinders are 1200 F, a bit cool for this rpm,
engine is smooth as silk.
4. At 3000 rpm number 3 (hottest) is 1275 F, number 2 (coolest) is 1200
F and engine is slightly rough.
5. At full throttle number 1 and 3 are 1300 F a bit high (2 is 1200, 4
is 1250), number 3 CHT is 250 F others about 225 F. One time I saw
number 3 almost to 1375 F. Engine is really pretty rough.
6. If number 3 EGT probe was in error it would have been different from
the others at 2800 rpm, but it wasn't.
7. The throttle movement from 3000 rpm to full throttle is about 20% of
the throw with little change in rpm. Number 3 EGT drops quickly after
going from full throttle back to about 3000 rpm.
8. I just finished my condition inspection and the compression varied
from about 71/80 (#4) to 63/80 (#3).
9. I have a 2 =BC" radiator hose (90 degree bend) going into the carb.
10. How can the EGT's be so high at higher throttle settings with a 255
main jet?
And most important, what can be causing the rough engine?
Thanks,
Chuck D.
Message 2
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| Subject: | Rough running 2200 |
What happens when you apply carb heat or apply choke when it is running
rough? Does it get better or worse?
Pete Krotje
Jabiru USA Sport Aircraft, LLC
_____
From: owner-jabiruengine-list-server@matronics.com
[mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Chuck
Deiterich
Sent: Monday, February 25, 2008 5:18 PM
Subject: JabiruEngine-List: Rough running 2200
1. Several flying hours ago my 2200 (solid lifters-#988) started running
rough at full throttle (~3140 rpm) and a bit rough about 3000 rpm (95
total
hours). The float bowl was running over. My float needle was the one
with
the weak spring so I put in a new float needle with the stronger spring.
Now, no fuel running over, engine off with Facet fuel pump for several
minutes.
2. Engine still is rough at high throttle, I thought it might be rich so
I
installed 4 EGT probes 120 mm from exhaust faces before changing any
jets.
My main jet is 255.
3. At 2800 rpm all 4 cylinders are 1200 F, a bit cool for this rpm,
engine
is smooth as silk.
4. At 3000 rpm number 3 (hottest) is 1275 F, number 2 (coolest) is 1200
F
and engine is slightly rough.
5. At full throttle number 1 and 3 are 1300 F a bit high (2 is 1200, 4
is
1250), number 3 CHT is 250 F others about 225 F. One time I saw number 3
almost to 1375 F. Engine is really pretty rough.
6. If number 3 EGT probe was in error it would have been different from
the
others at 2800 rpm, but it wasn=92t.
7. The throttle movement from 3000 rpm to full throttle is about 20% of
the
throw with little change in rpm. Number 3 EGT drops quickly after going
from
full throttle back to about 3000 rpm.
8. I just finished my condition inspection and the compression varied
from
about 71/80 (#4) to 63/80 (#3).
9. I have a 2 =BC" radiator hose (90 degree bend) going into the carb.
10. How can the EGT=92s be so high at higher throttle settings with a
255 main
jet?
And most important, what can be causing the rough engine?
Thanks,
Chuck D.
Message 3
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| Subject: | Rough running 2200 |
Chuck,
The needle valve seat usually leaks at anything above 2800 because the
seat
supplied is meant for gravity feed.
Also at the high throttle settings the fuel/air intake becomes uneven
because of induction pulses in the small induction pipes collector which
is
less than 1/2L in capacity. I am working on a 3.5L intake manifold to
solve
my engine which is now fuel injected.
During development I found that EGT R was about 100degC greater than EGT
L
and was told that this is common, but when I increased the butterfly
diameter EGT L became 100degC hotter than EGT R. I think the turbulence
in
that induction collector is disturbing fuel/air distribution and the
effect
is different at different RPM and worst at WOT.
When the fuel/air mix is out of balance the engine runs out of balance
or
slightly rough because the power strokes are not uniform. On one
occasion I
had the engine shake badly.
Peter H
_____
From: owner-jabiruengine-list-server@matronics.com
[mailto:owner-jabiruengine-list-server@matronics.com] On Behalf Of Chuck
Deiterich
Sent: Tuesday, 26 February 2008 9:18 AM
Subject: JabiruEngine-List: Rough running 2200
1. Several flying hours ago my 2200 (solid lifters-#988) started running
rough at full throttle (~3140 rpm) and a bit rough about 3000 rpm (95
total
hours). The float bowl was running over. My float needle was the one
with
the weak spring so I put in a new float needle with the stronger spring.
Now, no fuel running over, engine off with Facet fuel pump for several
minutes.
2. Engine still is rough at high throttle, I thought it might be rich so
I
installed 4 EGT probes 120 mm from exhaust faces before changing any
jets.
My main jet is 255.
3. At 2800 rpm all 4 cylinders are 1200 F, a bit cool for this rpm,
engine
is smooth as silk.
4. At 3000 rpm number 3 (hottest) is 1275 F, number 2 (coolest) is 1200
F
and engine is slightly rough.
5. At full throttle number 1 and 3 are 1300 F a bit high (2 is 1200, 4
is
1250), number 3 CHT is 250 F others about 225 F. One time I saw number 3
almost to 1375 F. Engine is really pretty rough.
6. If number 3 EGT probe was in error it would have been different from
the
others at 2800 rpm, but it wasn=92t.
7. The throttle movement from 3000 rpm to full throttle is about 20% of
the
throw with little change in rpm. Number 3 EGT drops quickly after going
from
full throttle back to about 3000 rpm.
8. I just finished my condition inspection and the compression varied
from
about 71/80 (#4) to 63/80 (#3).
9. I have a 2 =BC" radiator hose (90 degree bend) going into the carb.
10. How can the EGT=92s be so high at higher throttle settings with a
255 main
jet?
And most important, what can be causing the rough engine?
Thanks,
Chuck D.
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